Routed CO
This chapter provides information about Routed Central Office (Routed CO) configurations.
Topics in this chapter include:
Applicability
The information and configuration in this chapter are based on SR OS 11.0.R4.
Overview
In the Routed Central Office (Routed CO) model, subscriber management features are implemented on a Layer 3 subscriber interface, available in a VPRN or an IES service. Compared to regular Layer 3 interfaces, a subscriber interface supports multiple SAPs, see later.
Customer originated traffic enters an Access Node (AN) and can be aggregated via either a Layer 2 or a Layer 3 aggregation network before being handled by a Broadband Network Gateway (BNG). Alternatively, an AN can be directly connected to the BNG.
Routed CO supports numbered, unnumbered, and hybrid (combined numbered/unnumbered) subscriber interface configurations.
Enhanced Subscriber Management (ESM) is not mandatory for IPoEv4 in Routed CO, but is mandatory for PPPoE and all IPoEv6 scenarios.
The numbered and unnumbered scenarios in this example use an IES service with:
-
Dual Stack IPoEv4 + IPoEv6
-
Single stack PPPoEv4
General knowledge of Triple Play Service Delivery Architecture is assumed throughout this chapter. Refer to the 7450 ESS, 7750 SR, and VSR Triple Play Service Delivery Architecture Guide.
The Routed CO model offers through the subscriber and group interface construct:
Flexible subnet management
Subnets can be shared across multiple access nodes.
Support for different deployment models, for example:
VLAN/service model.
VLAN/subscriber model.
VLAN/service/subscriber model.
VLAN/access node model.
Per group-interface load balancing in multi-chassis redundancy configurations. Redundancy is out of the scope of this example.
The components needed in the Routed CO model are depicted in Components of the Routed CO Model.
For the Routed CO model two interface types are needed:
First, one or more subscriber interfaces must be created.
Second, one or more group interfaces must be created within the subscriber interface context.
Figure 1. Components of the Routed CO Model 
Subscriber Interface
A subscriber interface is a set of one or more group interfaces and identified by name.
A subscriber interface is created under an IES or VPRN service context, and supports up to 256 subnets (sum of IPv4 subnets and IPv6 prefixes).
Three types of subscriber interface configurations are available:
Numbered subscriber interface.
Unnumbered subscriber interface.
Hybrid subscriber interface (numbered and unnumbered combined).
Subnet/Prefix Assignment
For the numbered scenario, the subscriber interface is configured with
One or more IPv4 subnets.
One or more IPv6 subscriber prefixes:
For WAN-hosts, using the DHCPv6 Identity Association for Non-temporary Addresses (IA_NA) option or Stateless Address Auto Configuration (SLAAC) and the prefix length is /64.
For Prefix Delegation-hosts (PD-hosts), using the DHCPv6 Identity Association for Prefix Delegation (IA_PD) option and the prefix length is defined by the Delegated Prefix Length (DPL).
This allows for subscriber-host address assignment in these subnets/prefixes only.
For the unnumbered scenario, the subscriber interface is configured with:
IPv4:
No IPv4 subnets.
The keyword unnumbered plus an interface in the same routing instance (for example the system interface). The IP address of the interface referenced in the unnumbered command is used in IPCP negotiation.
IPv6:
No IPv6 prefixes.
allow-unmatching-prefixes.
This allows for subscriber-host address assignment in any subnet/prefix. For IPv4, the keywords unnumbered and allow-unmatching-subnets are mutually exclusive.
For the hybrid scenario the subscriber interface is configured with:
One or more IPv4 subnets and/or IPv6 subscriber prefixes.
For IPv4: the keyword allow-unmatching-subnets.
For IPv6: the keyword allow-unmatching-prefixes.
This allows for both subscriber-host address assignment within and outside of these subnets/prefixes.
Host IP Reachability
For the numbered scenario, host IP reachability requires:
Adding the subscriber interfaces to the Interior Gateway Protocol (IGP).
Or an export policy matching the subscriber interface subnets/prefixes.
For the unnumbered scenario, host IP reachability requires:
An export policy matching the addresses of all individual subscriber hosts (from protocol sub-mgmt).
For the hybrid scenario, host IP reachability requires:
An export policy matching both the subscriber interface subnets/prefixes as well as all individual subscriber hosts addresses.
Detailed examples of numbered/unnumbered/hybrid scenarios, including host IP reachability are included below.
Group Interface
A group interface is a set of one or more SAPs belonging to the same port and identified by name.
Configuration
This section covers:
The definition of subscriber and group interfaces.
A description of the numbered, unnumbered and hybrid scenarios.
Options ensuring host IP reachability throughout the network.
Subscriber Interface
The configuration of the subscriber interface appears as follows.
configure
service
ies 1
subscriber-interface "sub-int-1" create
address 10.1.1.254/24
address 10.1.2.254/24
ipv6
delegated-prefix-len 56
link-local-address FE80::EA:48:FF
subscriber-prefixes
prefix 2001:DB8:101::/48 wan-host
prefix 2001:DB8:102::/48 pd
prefix 2001:DB8:F101::/48 wan-host
prefix 2001:DB8:F102::/48 pd
exit
exit
exit
subscriber-interface "sub-int-2" create
address 10.2.1.254/24
address 10.2.2.254/24
ipv6
delegated-prefix-len 56
link-local-address FE80::EA:48:FF
subscriber-prefixes
prefix 2001:DB8:201::/48 wan-host
prefix 2001:DB8:202::/48 pd
prefix 2001:DB8:F201::/48 wan-host
prefix 2001:DB8:F202::/48 pd
exit
exit
exit
Notice that once a subnet/prefix is assigned to a subscriber interface, the subnet/prefix is tied to that interface, meaning that the same subnet/prefix cannot be used on another subscriber interface or regular interface in the same routing instance. When using VPRN for the Routed CO model, overlapping subnets/prefixes are allowed when on different VPRN services.
As long as no group interfaces are configured within the subscriber interface context, the subscriber interfaces are in the operationally down state as shown in the following output. The subscriber-interfaces, sub-int-1 and sub-int-2, are operational down since no group-interfaces have been assigned at this stage.
*A:BNG# show router "Base" interface
===============================================================================
Interface Table (Router: Base)
===============================================================================
Interface-Name Adm Opr(v4/v6) Mode Port/SapId
IP-Address PfxState
-------------------------------------------------------------------------------
sub-int-1 Up Down/Down IES Sub subscriber
10.1.1.254/24 n/a
10.1.2.254/24 n/a
2001:DB8:101::/48 INACCESSIBLE
2001:DB8:102::/48 INACCESSIBLE
2001:DB8:F101::/48 INACCESSIBLE
2001:DB8:F102::/48 INACCESSIBLE
FE80::EA:48:FF/64 INACCESSIBLE
sub-int-2 Up Down/Down IES Sub subscriber
10.2.1.254/24 n/a
10.2.2.254/24 n/a
2001:DB8:201::/48 INACCESSIBLE
2001:DB8:202::/48 INACCESSIBLE
2001:DB8:F201::/48 INACCESSIBLE
2001:DB8:F202::/48 INACCESSIBLE
FE80::EA:48:FF/64 INACCESSIBLE
system Up Up/Up Network system
192.0.2.75/32 n/a
2001:DB8::75/128 PREFERRED
toDHCP-1 Up Up/Up Network loopback
10.11.11.1/32 n/a
2001:DB8::11/128 PREFERRED
FE80::E84B:FFFF:FE00:0/64 PREFERRED
toRADIUS-1 Up Up/Down Network 1/1/10
192.168.202.75/24 n/a
-------------------------------------------------------------------------------
Interfaces : 5
===============================================================================
*A:BNG#
The corresponding IPv4 routing table looks as follows.
*A:BNG# show router "Base" route-table ipv4
===============================================================================
Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
10.11.11.1/32 Local Local 00h30m12s 0
toDHCP-1 0
192.0.2.75/32 Local Local 00h30m12s 0
system 0
192.168.202.0/24 Local Local 00h29m54s 0
toRADIUS-1 0
-------------------------------------------------------------------------------
No. of Routes: 3
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:BNG#
The corresponding IPv6 routing table looks as follows.
*A:BNG# show router "Base" route-table ipv6
===============================================================================
IPv6 Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
2001:DB8::11/128 Local Local 00h30m19s 0
toDHCP-1 0
2001:DB8::75/128 Local Local 00h30m21s 0
system 0
-------------------------------------------------------------------------------
No. of Routes: 2
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:BNG#
No subscriber interface subnets/prefixes are present in the IPv4 and the IPv6 routing table as the subscriber interfaces are operational down.
Group Interface
A group interface is created under the subscriber-interface hierarchy.
configure
service
ies 1
subscriber-interface "sub-int-1" create
group-interface "grp-int-1-1" create
ipv6
exit
sap 1/1/1:111 create
exit
sap 1/1/1:112 create
exit
exit
group-interface "grp-int-1-2" create
ipv6
exit
sap 1/1/1:121 create
exit
exit
exit
subscriber-interface "sub-int-2" create
group-interface "grp-int-2-1" create
ipv6
exit
sap 1/1/2:211 create
exit
exit
group-interface "grp-int-2-2" create
ipv6
exit
sap 1/1/3:221 create
exit
sap 1/1/3:222 create
exit
exit
exit
exit
Static SAPs are created manually under the group-interface context. Managed SAPs (MSAPs) are dynamically created when a trigger packet (DHCP, DHCPv6, ARP, PPPoE) is successfully authenticated, which eliminates the provisioning of static SAPs. The creation and use of capture and managed SAPs (MSAPs) is explained in the example on Managed SAPs with Routed CO.
A group interface is operationally up when at least one of its statically configured SAPs is operationally up or when no static SAPs are configured while the parameter oper-up-while-empty under the group-interface context is enabled. The following output shows all group interfaces are operationally up.
*A:BNG# show router "Base" interface ipv4
===============================================================================
Interface Table (Router: Base)
===============================================================================
Interface-Name Adm Opr(v4/v6) Mode Port/SapId
IP-Address PfxState
-------------------------------------------------------------------------------
grp-int-1-1 Up Up/Up IES Grp 1/1/1
grp-int-1-2 Up Up/Up IES Grp 1/1/1
grp-int-2-1 Up Up/Up IES Grp 1/1/2
grp-int-2-2 Up Up/Up IES Grp 1/1/3
sub-int-1 Up Up/Up IES Sub subscriber
10.1.1.254/24 n/a
10.1.2.254/24 n/a
sub-int-2 Up Up/Up IES Sub subscriber
10.2.1.254/24 n/a
10.2.2.254/24 n/a
system Up Up/Up Network system
192.0.2.75/32 n/a
toDHCP-1 Up Up/Up Network loopback
10.11.11.1/32 n/a
toRADIUS-1 Up Up/Down Network 1/1/10
192.168.202.75/24 n/a
-------------------------------------------------------------------------------
Interfaces : 9
===============================================================================
*A:BNG#
The IPv4 routing table includes the subnets configured on the subscriber-interfaces.
*A:BNG# show router "Base" route-table ipv4
===============================================================================
Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
10.1.1.0/24 Local Local 00h25m32s 0
sub-int-1 0
10.1.2.0/24 Local Local 00h25m32s 0
sub-int-1 0
10.2.1.0/24 Local Local 00h25m32s 0
sub-int-2 0
10.2.2.0/24 Local Local 00h25m32s 0
sub-int-2 0
10.11.11.1/32 Local Local 01h01m53s 0
toDHCP-1 0
192.0.2.75/32 Local Local 01h01m53s 0
system 0
192.168.202.0/24 Local Local 01h01m36s 0
toRADIUS-1 0
-------------------------------------------------------------------------------
No. of Routes: 7
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:BNG#
For IPv6, the interface table looks as follows.
*A:BNG# show router "Base" interface ipv6
===============================================================================
Interface Table (Router: Base)
===============================================================================
Interface-Name Adm Opr(v4/v6) Mode Port/SapId
IP-Address PfxState
-------------------------------------------------------------------------------
grp-int-1-1 Up Up/Up IES Grp 1/1/1
grp-int-1-2 Up Up/Up IES Grp 1/1/1
grp-int-2-1 Up Up/Up IES Grp 1/1/2
grp-int-2-2 Up Up/Up IES Grp 1/1/3
sub-int-1 Up Up/Up IES Sub subscriber
2001:DB8:101::/48 PREFERRED
2001:DB8:102::/48 PREFERRED
2001:DB8:F101::/48 PREFERRED
2001:DB8:F102::/48 PREFERRED
FE80::EA:48:FF/64 PREFERRED
sub-int-2 Up Up/Up IES Sub subscriber
2001:DB8:201::/48 PREFERRED
2001:DB8:202::/48 PREFERRED
2001:DB8:F201::/48 PREFERRED
2001:DB8:F202::/48 PREFERRED
FE80::EA:48:FF/64 PREFERRED
system Up Up/Up Network system
2001:DB8::75/128 PREFERRED
toDHCP-1 Up Up/Up Network loopback
2001:DB8::11/128 PREFERRED
FE80::E84B:FFFF:FE00:0/64 PREFERRED
toRADIUS-1 Up Up/Down Network 1/1/10
- -
-------------------------------------------------------------------------------
Interfaces : 9
===============================================================================
*A:BNG# #
The IPv6 routing table includes the prefixes configured on the subscriber interfaces.
*A:BNG# show router "Base" route-table ipv6
===============================================================================
IPv6 Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
2001:DB8::11/128 Local Local 14d04h08m 0
toDHCP-1 0
2001:DB8::75/128 Local Local 14d04h08m 0
system 0
2001:DB8:101::/48 Local Local 14d03h10m 0
sub-int-1 0
2001:DB8:102::/48 Local Local 14d03h10m 0
sub-int-1 0
2001:DB8:201::/48 Local Local 14d03h08m 0
sub-int-2 0
2001:DB8:202::/48 Local Local 14d03h08m 0
sub-int-2 0
2001:DB8:F101::/48 Local Local 14d03h10m 0
sub-int-1 0
2001:DB8:F102::/48 Local Local 14d03h10m 0
sub-int-1 0
2001:DB8:F201::/48 Local Local 14d03h08m 0
sub-int-2 0
2001:DB8:F202::/48 Local Local 14d03h08m 0
sub-int-2 0
-------------------------------------------------------------------------------
No. of Routes: 10
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:BNG#
Numbered Scenario
Numbered Scenario For IES 1 depicts the numbered scenario outlined below, including the connecting subscribers and subscriber hosts. Subscribers sub-11 and sub-44 are using PPPv4 hosts, and subscribers sub-22 and sub-33 are using dual stack DHCP hosts. Their VLANs and the MAC addresses are shown, as are the IP addresses and prefixes assigned once they are connected.
The configuration for the numbered scenario is shown below. Only the configuration items specific to the numbered scenario are shown.
In the numbered scenario the subscriber interfaces have following configuration:
IPv4
Subnets.
no allow-unmatching-subnets.
no unnumbered.
IPv6
A delegated prefix length.
subscriber prefixes.
no allow-unmatching-prefixes.
configure service ies 1 subscriber-interface "sub-int-1" create address 10.1.1.254/24 address 10.1.2.254/24 ipv6 delegated-prefix-len 56 link-local-address FE80::EA:4B:FF subscriber-prefixes prefix 2001:DB8:101::/48 wan-host prefix 2001:DB8:102::/48 pd exit exit group-interface "grp-int-1-1" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" local-proxy-arp sap 1/1/1:111 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/1:112 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit pppoe ---snip--- no shutdown exit exit group-interface "grp-int-1-2" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" local-proxy-arp sap 1/1/1:121 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/1:122 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit pppoe ---snip--- no shutdown exit exit exit subscriber-interface "sub-int-2" create address 10.2.1.254/24 address 10.2.2.254/24 ipv6 delegated-prefix-len 56 link-local-address FE80::EA:4B:FF subscriber-prefixes prefix 2001:DB8:201::/48 wan-host prefix 2001:DB8:202::/48 pd exit exit group-interface "grp-int-2-1" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" local-proxy-arp sap 1/1/2:211 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/2:212 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit pppoe ---snip--- no shutdown exit exit group-interface "grp-int-2-2" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" local-proxy-arp sap 1/1/3:221 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/3:222 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit pppoe ---snip--- no shutdown exit exit exit no shutdown
The following parameters are mandatory for the routed CO model:
lease-populate — DHCPv4 lease state population is enabled by default on a group-interface with DHCPv4 configured as no shutdown. The number of leases allowed on each SAP of the group-interface must be configured. By default one single DHCPv4 host is allowed on each SAP. This parameter enables the creation of an ESM host table entry for each DHCPv4 lease. For DHCPv6 the ESM host table entry creation is implicit: no CLI parameter is required.
arp-populate — The ARP table is populated with dynamically learned entries from the DHCP lease state table or static entries from the static host table. The BNG does not send downstream ARPs for those managed ARP table entries.
local-proxy-arp — Enables user to user traffic in a split-horizon environment. The BNG responds with its own MAC address to ARP requests targeting subnets configured on the subscriber interface. If the ARP request is targeting a host of the same subscriber on the same SAP, the ARP request is silently discarded. This prevents traffic within a single bridged home to be attracted to the BNG. Local-proxy-arp is enabled by default.
anti-spoof — Checks the source MAC and/or source IP of the upstream subscriber traffic. This parameter is configured at the SAP level with values ip-mac (default), ip or nh-mac. With ESM enabled, anti-spoof must include the source mac (values ip-mac or nh-mac).
Optional settings are:
description — Can be used to assign a descriptive text to the item and used for administrative reasons.
delayed-enable — To be used in redundant configurations. It is expressed in seconds and defines the additional time the BNG waits before the interface is enabled.
Verification
The interfaces on the BNG are listed using following command. Notice that all subscriber and group interfaces are operational up for IPv4 and IPv6.
A:BNG# show router "Base" interface
===============================================================================
Interface Table (Router: Base)
===============================================================================
Interface-Name Adm Opr(v4/v6) Mode Port/SapId
IP-Address PfxState
-------------------------------------------------------------------------------
grp-int-1-1 Up Up/Up IES Grp 1/1/1
grp-int-1-2 Up Up/Up IES Grp 1/1/1
grp-int-2-1 Up Up/Up IES Grp 1/1/2
grp-int-2-2 Up Up/Up IES Grp 1/1/3
sub-int-1 Up Up/Up IES Sub subscriber
10.1.1.254/24 n/a
10.1.2.254/24 n/a
2001:DB8:101::/48 PREFERRED
2001:DB8:102::/48 PREFERRED
FE80::EA:48:FF/64 PREFERRED
sub-int-2 Up Up/Up IES Sub subscriber
10.2.1.254/24 n/a
10.2.2.254/24 n/a
2001:DB8:201::/48 PREFERRED
2001:DB8:202::/48 PREFERRED
FE80::EA:48:FF/64 PREFERRED
system Up Up/Up Network system
192.0.2.75/32 n/a
2001:DB8::75/128 PREFERRED
toDHCP-1 Up Up/Up Network loopback
10.11.11.1/32 n/a
2001:DB8::11/128 PREFERRED
FE80::E84B:FFFF:FE00:0/64 PREFERRED
toR1 Up Up/Up Network 1/1/12
192.168.12.1/24 n/a
2001:DEAD::1/64 PREFERRED
FE80::E84B:FFFF:FE00:0/64 PREFERRED
toRADIUS-1 Up Up/Down Network 1/1/10
192.168.202.75/24 n/a
-------------------------------------------------------------------------------
Interfaces : 10
===============================================================================
A:BNG#
Successfully created hosts have forwarding state Fwding. Hosts not in the Fwding state cannot forward any data.
A:BNG# show service id 1 subscriber-hosts
=============================================================
Subscriber Host table
=============================================================
Sap Subscriber
IP Address
MAC Address PPPoE-SID Origin Fwding State
-------------------------------------------------------------
1/1/1:111 sub-11
10.1.1.11
00:00:00:11:11:11 1 IPCP Fwding
1/1/1:112 sub-22
10.1.1.12
00:00:00:22:22:22 N/A DHCP Fwding
1/1/1:112 sub-22
2001:DB8:101:1::1/128
00:00:00:22:22:22 N/A IPoE-DHCP6 Fwding
1/1/1:112 sub-22
2001:DB8:102:200::/56
00:00:00:22:22:22 N/A IPoE-DHCP6 Fwding
1/1/1:122 sub-33
10.1.1.13
00:00:00:33:33:33 N/A DHCP Fwding
1/1/1:122 sub-33
2001:DB8:101:2::1/128
00:00:00:33:33:33 N/A IPoE-DHCP6 Fwding
1/1/1:122 sub-33
2001:DB8:102:300::/56
00:00:00:33:33:33 N/A IPoE-DHCP6 Fwding
1/1/3:222 sub-44
10.2.2.11
00:00:00:44:44:44 1 IPCP Fwding
-------------------------------------------------------------
Number of subscriber hosts : 8
=============================================================
A:BNG#
The list of active subscribers can be displayed as follows.
A:BNG# show service active-subscribers
===============================================================================
Active Subscribers
===============================================================================
-------------------------------------------------------------------------------
Subscriber sub-11 (sub-prof-1)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
(1) SLA Profile Instance sap:1/1/1:111 - sla:sla-prof-1
-------------------------------------------------------------------------------
IP Address
MAC Address PPPoE-SID Origin
--------------------------------------------------------
10.1.1.11
00:00:00:11:11:11 1 IPCP
-------------------------------------------------------------------------------
Subscriber sub-22 (sub-prof-1)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
(1) SLA Profile Instance sap:1/1/1:112 - sla:sla-prof-1
-------------------------------------------------------------------------------
IP Address
MAC Address PPPoE-SID Origin
--------------------------------------------------------
10.1.1.12
00:00:00:22:22:22 N/A DHCP
2001:DB8:101:1::1/128
00:00:00:22:22:22 N/A IPoE-DHCP6
2001:DB8:102:200::/56
00:00:00:22:22:22 N/A IPoE-DHCP6
-------------------------------------------------------------------------------
Subscriber sub-33 (sub-prof-1)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
(1) SLA Profile Instance sap:1/1/1:122 - sla:sla-prof-1
-------------------------------------------------------------------------------
IP Address
MAC Address PPPoE-SID Origin
--------------------------------------------------------
10.1.1.13
00:00:00:33:33:33 N/A DHCP
2001:DB8:101:2::1/128
00:00:00:33:33:33 N/A IPoE-DHCP6
2001:DB8:102:300::/56
00:00:00:33:33:33 N/A IPoE-DHCP6
-------------------------------------------------------------------------------
Subscriber sub-44 (sub-prof-1)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
(1) SLA Profile Instance sap:1/1/3:222 - sla:sla-prof-1
-------------------------------------------------------------------------------
IP Address
MAC Address PPPoE-SID Origin
--------------------------------------------------------
10.2.2.11
00:00:00:44:44:44 1 IPCP
-------------------------------------------------------------------------------
Number of active subscribers : 4
-------------------------------------------------------------------------------
A:BNG#
Manually cross-referencing the SAPs from this output with the actual configuration shows the following for IPv4, and is depicted in Numbered Scenario For IES 1.
Sub-11 and sub-22 are connected to the same subscriber and group interface (sub-int-1 and grp-int-1-1) but via different SAPs (1/1/1:111 and 1/1/1:112) and are sharing the same IPv4 subnet.
Sub-33 is also connected to the same subscriber interface (sub-int-1) but via a different group-interface (grp-int-1-2). Sub-33 shares the same IPv4 subnet as sub-11 and sub-12, showing that the same subnet is shared across multiple group-interfaces.
Sub-44 is connected to a different subscriber and group interface, and does not share a subnet with the other subscribers.
An alternative way to find where, for example, subscriber sub-33 is connected is shown below.
*A:BNG# show service active-subscribers subscriber "sub-33" detail
===============================================================================
Active Subscribers
===============================================================================
-------------------------------------------------------------------------------
Subscriber sub-11 (sub-prof-1)
-------------------------------------------------------------------------------
I. Sched. Policy : N/A
---snip---
Oper-Rate-Limit : Maximum
* indicates that the corresponding row element may have been truncated.
-------------------------------------------------------------------------------
(1) SLA Profile Instance
- sap:1/1/1:112 (IES 1 - grp-int-1-2)
- sla:sla-prof-1
-------------------------------------------------------------------------------
Description : (Not Specified)
---snip---
An alternative to find where, for example, IP address 10.1.1.13 is connected is shown below.
*A:BNG# show service id 1 dhcp lease-state ip-address 10.1.1.13 detail
===============================================================================
DHCP lease states for service 1
===============================================================================
Service ID : 1
IP Address : 10.1.1.13
Client HW Address : 00:00:00:33:33:33
Subscriber-interface : sub-int-1
Group-interface : grp-int-1-2
SAP : 1/1/1:122
---snip---
Sub-Ident : "sub-33"
Sub-Profile-String : "sub-prof-1"
SLA-Profile-String : "sla-prof-1"
App-Profile-String : ""
---snip---
DHCP Server Addr : 10.11.11.1
Radius User-Name : "00:00:00:33:33:33"
-------------------------------------------------------------------------------
Number of lease states : 1
===============================================================================
*A:BNG#
For IPv6, the situation is as follows:
Sub-22 and sub-33 are connected to the same subscriber interface (sub-int-1) but to different group interfaces. Both subscribers share the same IPv6 prefix for prefix-delegation (PD) and wan-host.
With these subscriber hosts connected, the IPv4 routing table (RIB) for the base router looks as follows.
*A:BNG# show router "Base" route-table ipv4
===============================================================================
Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
10.1.1.0/24 Local Local 02h25m15s 0
sub-int-1 0
10.1.1.11/32 Remote Sub Mgmt 02h25m10s 0
[grp-int-1-1] 0
10.1.1.12/32 Remote Sub Mgmt 00h49m52s 0
[grp-int-1-1] 0
10.1.1.13/32 Remote Sub Mgmt 00h47m40s 0
[grp-int-1-2] 0
10.1.2.0/24 Local Local 02h25m15s 0
sub-int-1 0
10.2.1.0/24 Local Local 02h25m15s 0
sub-int-2 0
10.2.2.0/24 Local Local 02h25m15s 0
sub-int-2 0
10.2.2.11/32 Remote Sub Mgmt 02h25m10s 0
[grp-int-2-2] 0
10.11.11.1/32 Local Local 02h25m33s 0
toDHCP-1 0
192.0.2.75/32 Local Local 02h25m33s 0
system 0
192.0.2.76/32 Remote ISIS 02h24m43s 15
192.168.12.2 10
192.168.12.0/24 Local Local 02h25m15s 0
toR1 0
192.168.202.0/24 Local Local 02h25m15s 0
toRADIUS-1 0
-------------------------------------------------------------------------------
No. of Routes: 13
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:BNG#
The IPv6 routing table (RIB) for the base router displays as follows.
*A:BNG# show router "Base" route-table ipv6
===============================================================================
IPv6 Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
2001:DB8::11/128 Local Local 02h27m23s 0
toDHCP-1 0
2001:DB8::75/128 Local Local 02h27m24s 0
system 0
2001:DB8::76/128 Remote ISIS 02h26m32s 15
FE80::E84C:FFFF:FE00:0-"toR1" 10
2001:DB8:101::/48 Local Local 02h27m06s 0
sub-int-1 0
2001:DB8:101:1::1/128 Remote Sub Mgmt 01h13m43s 0
[grp-int-1-1] 0
2001:DB8:101:2::1/128 Remote Sub Mgmt 01h13m25s 0
[grp-int-1-2] 0
2001:DB8:102::/48 Local Local 02h27m06s 0
sub-int-1 0
2001:DB8:102:200::/56 Remote Sub Mgmt 01h13m43s 0
[grp-int-1-1] 0
2001:DB8:102:300::/56 Remote Sub Mgmt 01h13m25s 0
[grp-int-1-2] 0
2001:DB8:201::/48 Local Local 02h27m06s 0
sub-int-2 0
2001:DB8:202::/48 Local Local 02h27m06s 0
sub-int-2 0
2001:DEAD::/64 Local Local 02h27m05s 0
toR1 0
-------------------------------------------------------------------------------
No. of Routes: 12
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:BNG#
The corresponding IPv4 FIB on card 1 looks as follows.
*A:BNG# show router "Base" fib 1 ipv4
===============================================================================
FIB Display
===============================================================================
Prefix Protocol
NextHop
-------------------------------------------------------------------------------
10.1.1.0/24 LOCAL
10.1.1.0 (sub-int-1)
10.1.2.0/24 LOCAL
10.1.2.0 (sub-int-1)
10.2.1.0/24 LOCAL
10.2.1.0 (sub-int-2)
10.2.2.0/24 LOCAL
10.2.2.0 (sub-int-2)
10.11.11.1/32 LOCAL
10.11.11.1 (toDHCP-1)
192.0.2.75/32 LOCAL
192.0.2.75 (system)
192.0.2.76/32 ISIS
192.168.12.2 (toR1)
192.168.12.0/24 LOCAL
192.168.12.0 (toR1)
192.168.202.0/24 LOCAL
192.168.202.0 (toRADIUS-1)
-------------------------------------------------------------------------------
Total Entries : 9
-------------------------------------------------------------------------------
===============================================================================
*A:BNG#
The corresponding IPv6 FIB on card 1 is as follows.
*A:BNG# show router "Base" fib 1 ipv6
===============================================================================
FIB Display
===============================================================================
Prefix Protocol
NextHop
-------------------------------------------------------------------------------
2001:DB8::11/128 LOCAL
2001:DB8::11 (toDHCP-1)
2001:DB8::75/128 LOCAL
2001:DB8::75 (system)
2001:DB8::76/128 ISIS
FE80::E84C:FFFF:FE00:0 (toR1)
2001:DB8:101::/48 LOCAL
2001:DB8:101:: (sub-int-1)
2001:DB8:102::/48 LOCAL
2001:DB8:102:: (sub-int-1)
2001:DB8:201::/48 LOCAL
2001:DB8:201:: (sub-int-2)
2001:DB8:202::/48 LOCAL
2001:DB8:202:: (sub-int-2)
2001:DEAD::/64 LOCAL
2001:DEAD:: (toR1)
-------------------------------------------------------------------------------
Total Entries : 8
-------------------------------------------------------------------------------
===============================================================================
*A:BNG#
The addresses of the individual subscriber hosts show up in the RIB but they do not show up in the FIB.
/32 for IPv4-hosts.
/DPL (Delegated Prefix Length) for IPv6 DP hosts, /56 in this example.
/128 or /64 for IPv6 wan host.
Downstream traffic is forwarded based on a subscriber host table lookup. For specific network designs, subscriber host IPv4 addresses can optionally be included in the FIB with the populate-host-routes statement added to the subnet configuration. This is out of scope of this example.
Unnumbered Scenario
Unnumbered Scenario for IES 1 depicts the unnumbered scenario outlined below, including the connecting subscribers and subscriber hosts. Sub-11 and sub-44 are using single stack PPPoEv4 hosts, and sub-22 and sub-33 are using dual stack DHCP hosts. Their VLANs and the MAC addresses are shown, as are the IP addresses and prefixes assigned once they are connected.
The configuration for the unnumbered scenario is show below. Only the configuration items specific to the unnumbered scenario are shown.
In the unnumbered scenario the subscriber interfaces have following properties:
IPv4:
No subnets configured.
unnumbered, with an IPv4 interface or an IPv4 address used for IPCP negotiation.
no allow-unmatching-subnets.
IPv6:
No subscriber prefixes configured.
allow-unmatching-prefixes.
configure service ies 1 subscriber-interface "sub-int-1" create unnumbered "system" ipv6 delegated-prefix-len 56 allow-unmatching-prefixes link-local-address FE80::EA:4B:FF exit group-interface "grp-int-1-1" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" sap 1/1/1:111 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/1:112 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit pppoe ---snip--- no shutdown exit exit group-interface "grp-int-1-2" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" sap 1/1/1:121 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/1:122 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit pppoe ---snip--- no shutdown exit exit exit subscriber-interface "sub-int-2" create unnumbered "system" ipv6 delegated-prefix-len 56 allow-unmatching-prefixes link-local-address FE80::EA:4B:FF exit group-interface "grp-int-2-1" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" sap 1/1/2:211 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/2:212 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit pppoe ---snip--- no shutdown exit exit group-interface "grp-int-2-2" create ipv6 ---snip--- exit arp-populate dhcp ---snip--- lease-populate 100 no shutdown exit authentication-policy "auth-pol-1" sap 1/1/3:221 create anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit sap 1/1/3:222 create sub-sla-mgmt anti-spoof ip-mac sub-sla-mgmt ---snip--- exit exit exit pppoe ---snip--- no shutdown exit exit exit no shutdown
The same mandatory and optional settings as for the numbered scenario apply.
Verification
The interfaces on the BNG are listed using following command. Notice that all subscriber and group interfaces are operational up for IPv4 and IPv6.
A:BNG# show router "Base" interface
===============================================================================
Interface Table (Router: Base)
===============================================================================
Interface-Name Adm Opr(v4/v6) Mode Port/SapId
IP-Address PfxState
-------------------------------------------------------------------------------
grp-int-1-1 Up Up/Up IES Grp 1/1/1
grp-int-1-2 Up Up/Up IES Grp 1/1/1
grp-int-2-1 Up Up/Up IES Grp 1/1/2
grp-int-2-2 Up Up/Up IES Grp 1/1/3
lb-pool4-1 Up Up/Down Network loopback
10.1.1.254/24 n/a
lb-pool4-2 Up Up/Down Network loopback
10.1.2.254/24 n/a
lb-pool4-3 Up Up/Down Network loopback
10.2.1.254/24 n/a
lb-pool4-4 Up Up/Down Network loopback
10.2.2.254/24 n/a
sub-int-1 Up Up/Up IES Sub subscriber
Unnumbered If[system] n/a
FE80::EA:4B:FF/64 PREFERRED
sub-int-2 Up Up/Up IES Sub subscriber
Unnumbered If[system] n/a
FE80::EA:4B:FF/64 PREFERRED
system Up Up/Up Network system
192.0.2.75/32 n/a
2001:DB8::75/128 PREFERRED
toDHCP-1 Up Up/Up Network loopback
10.11.11.1/32 n/a
2001:DB8::11/128 PREFERRED
FE80::E84B:FFFF:FE00:0/64 PREFERRED
toR1 Up Up/Down Network 1/1/12
192.168.12.1/24 n/a
toRADIUS-1 Up Up/Down Network 1/1/10
192.168.202.75/24 n/a
-------------------------------------------------------------------------------
Interfaces : 14
===============================================================================
A:BNG#
Successfully created hosts have forwarding state Fwding. Hosts not in the Fwding state cannot forward any data.
*A:BNG# show service id 1 subscriber-hosts
=============================================================
Subscriber Host table
=============================================================
Sap Subscriber
IP Address
MAC Address PPPoE-SID Origin Fwding State
-------------------------------------------------------------
1/1/1:111 sub-11
10.1.1.101
00:00:00:11:11:11 1 IPCP Fwding
1/1/1:122 sub-22
10.2.2.1
00:00:00:22:22:22 N/A DHCP Fwding
1/1/1:122 sub-22
2001:DB8:101::1/128
00:00:00:22:22:22 N/A IPoE-DHCP6 Fwding
1/1/1:122 sub-22
2001:DB8:102::/56
00:00:00:22:22:22 N/A IPoE-DHCP6 Fwding
1/1/2:211 sub-33
10.2.2.2
00:00:00:33:33:33 N/A DHCP Fwding
1/1/2:211 sub-33
2001:DB8:101:1::1/128
00:00:00:33:33:33 N/A IPoE-DHCP6 Fwding
1/1/2:211 sub-33
2001:DB8:102:100::/56
00:00:00:33:33:33 N/A IPoE-DHCP6 Fwding
1/1/2:212 sub-44
10.1.1.102
00:00:00:44:44:44 1 IPCP Fwding
-------------------------------------------------------------
Number of subscriber hosts : 8
=============================================================
*A:BNG#
A variant of the show service active-subscribers command shows the subscriber hierarchy.
*A:BNG# show service active-subscribers hierarchy
===============================================================================
Active Subscriber hierarchy
===============================================================================
-- sub-11 (sub-prof-1)
|
|-- sap:1/1/1:111 - sla:sla-prof-1
| |
| |-- 10.1.1.101
| | 00:00:00:11:11:11 - 1 (IPCP)
| |
-- sub-22 (sub-prof-1)
|
|-- sap:1/1/1:122 - sla:sla-prof-1
| |
| |-- 10.2.2.1
| | 00:00:00:22:22:22 - N/A (DHCP)
| |
| |-- 2001:DB8:101::1/128
| | 00:00:00:22:22:22 - N/A (IPoE-DHCP6)
| |
| |-- 2001:DB8:102::/56
| | 00:00:00:22:22:22 - N/A (IPoE-DHCP6)
| |
-- sub-33 (sub-prof-1)
|
|-- sap:1/1/2:211 - sla:sla-prof-1
| |
| |-- 10.2.2.2
| | 00:00:00:33:33:33 - N/A (DHCP)
| |
| |-- 2001:DB8:101:1::1/128
| | 00:00:00:33:33:33 - N/A (IPoE-DHCP6)
| |
| |-- 2001:DB8:102:100::/56
| | 00:00:00:33:33:33 - N/A (IPoE-DHCP6)
| |
-- sub-44 (sub-prof-1)
|
|-- sap:1/1/2:212 - sla:sla-prof-1
| |
| |-- 10.1.1.102
| | 00:00:00:44:44:44 - 1 (IPCP)
| |
===============================================================================
*A:BNG#
Manually cross-referencing the SAPs from this output with the actual configuration shows the following for IPv4, and is represented in Unnumbered Scenario for IES 1.
Sub-11 and sub-44 share the same IPv4 subnet even though they are connected to different subscriber interfaces.
Sub-22 and sub-33 share the same subnet even though they are connected to different subscriber interfaces.
For IPv6 the situation is as follows:
Sub-22 and sub-33 are in different subscriber interfaces and do not share IPv6 prefixes in this example.
With these subscriber hosts are connected, the IPv4 RIB for the base router looks as follows.
A:BNG# show router "Base" route-table ipv4
===============================================================================
Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
10.1.1.0/24 Local Local 00h49m42s 0
lb-pool4-1 0
10.1.1.101/32 Remote Sub Mgmt 00h23m24s 0
[grp-int-1-1] 0
10.1.1.102/32 Remote Sub Mgmt 00h02m32s 0
[grp-int-2-1] 0
10.1.2.0/24 Local Local 00h49m42s 0
lb-pool4-2 0
10.2.1.0/24 Local Local 00h49m42s 0
lb-pool4-3 0
10.2.2.0/24 Local Local 00h49m42s 0
lb-pool4-4 0
10.2.2.1/32 Remote Sub Mgmt 00h27m18s 0
[grp-int-1-2] 0
10.2.2.2/32 Remote Sub Mgmt 00h27m10s 0
[grp-int-2-1] 0
10.11.11.1/32 Local Local 00h49m42s 0
toDHCP-1 0
192.0.2.75/32 Local Local 00h49m42s 0
system 0
192.0.2.76/32 Remote ISIS 00h41m48s 15
192.168.12.2 10
192.168.12.0/24 Local Local 00h49m24s 0
toR1 0
192.168.202.0/24 Local Local 00h49m24s 0
toRADIUS-1 0
-------------------------------------------------------------------------------
No. of Routes: 13
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
A:BNG#
The IPv6 RIB for the base router looks as follows.
.A:BNG# show router "Base" route-table ipv6
===============================================================================
IPv6 Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
2001:DB8::11/128 Local Local 01h03m27s 0
toDHCP-1 0
2001:DB8::75/128 Local Local 00h06m34s 0
system 0
2001:DB8:101::1/128 Remote Sub Mgmt 00h36m12s 0
[grp-int-1-2] 0
2001:DB8:101:1::1/128 Remote Sub Mgmt 00h35m58s 0
[grp-int-2-1] 0
2001:DB8:102::/56 Remote Sub Mgmt 00h36m12s 0
[grp-int-1-2] 0
2001:DB8:102:100::/56 Remote Sub Mgmt 00h35m58s 0
[grp-int-2-1] 0
-------------------------------------------------------------------------------
No. of Routes: 6
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
A:BNG# #
The corresponding IPv4 FIB on card 1 looks as follows.
A:BNG# show router "Base" fib 1 ipv4
===============================================================================
FIB Display
===============================================================================
Prefix Protocol
NextHop
-------------------------------------------------------------------------------
10.1.1.0/24 LOCAL
10.1.1.0 (lb-pool4-1)
10.1.1.101/32 LOCAL
10.1.1.101 (sub-int-1)
10.1.1.102/32 LOCAL
10.1.1.102 (sub-int-2)
10.1.2.0/24 LOCAL
10.1.2.0 (lb-pool4-2)
10.2.1.0/24 LOCAL
10.2.1.0 (lb-pool4-3)
10.2.2.0/24 LOCAL
10.2.2.0 (lb-pool4-4)
10.2.2.1/32 LOCAL
10.2.2.1 (sub-int-1)
10.2.2.2/32 LOCAL
10.2.2.2 (sub-int-2)
10.11.11.1/32 LOCAL
10.11.11.1 (toDHCP-1)
192.0.2.75/32 LOCAL
192.0.2.75 (system)
192.0.2.76/32 ISIS
192.168.12.2 (toR1)
192.168.12.0/24 LOCAL
192.168.12.0 (toR1)
192.168.202.0/24 LOCAL
192.168.202.0 (toRADIUS-1)
-------------------------------------------------------------------------------
Total Entries : 13
-------------------------------------------------------------------------------
===============================================================================
A:BNG#
The corresponding IPv6 FIB on card 1 looks as follows:
A:BNG# show router "Base" fib 1 ipv6
===============================================================================
FIB Display
===============================================================================
Prefix Protocol
NextHop
-------------------------------------------------------------------------------
2001:DB8::11/128 LOCAL
2001:DB8::11 (toDHCP-1)
2001:DB8::75/128 LOCAL
2001:DB8::75 (system)
2001:DB8:101::1/128 LOCAL
2001:DB8:101::1 (sub-int-1)
2001:DB8:101:1::1/128 LOCAL
2001:DB8:101:1::1 (sub-int-2)
2001:DB8:102::/56 LOCAL
2001:DB8:102:: (sub-int-1)
2001:DB8:102:100::/56 LOCAL
2001:DB8:102:100:: (sub-int-2)
-------------------------------------------------------------------------------
Total Entries : 6
-------------------------------------------------------------------------------
===============================================================================
A:BNG#
The addresses of the individual subscriber hosts appear in the RIB and the FIB, which is the main difference with the numbered model. The forwarding plane here needs the individual addresses to forward the traffic towards the individual subscriber hosts.
Hybrid Scenario
An alternative to the scenarios described above does exist in the form of a mixed numbered/unnumbered (hybrid) scenario as depicted in Hybrid Configuration.
The subscriber interface is configured with
One or more IPv4 subnets and/or IPv6 subscriber prefixes.
For IPv4: the keyword allow-unmatching-subnets.
For IPv6: the keyword allow-unmatching-prefixes.
No explicit configuration is shown as it is a mix of the numbered and the unnumbered scenario described above, and as such the behavior is mixed.
Host IP Reachability
To ensure reachability to the individual subscriber hosts, the subnets and prefixes of the subscriber interfaces/subscriber hosts need to be distributed to other routers in the network.
Three options are available:
Without an export policy.
With an export policy using, for example, from protocol direct.
With an export policy using, for example, from protocol sub-mgmt.
Option 1 – No Export Policy
The key properties for the first option are:
Subscriber interface subnets and prefixes are distributed into the network by adding the subscriber interfaces as passive interfaces to the routing protocol.
It is used in combination with IGP based route distribution.
It works with the numbered model only.
In this option the BNG uses IS-IS as IGP and no export policy is needed.
configure
router
isis
area-id 48.0001
multi-topology
ipv6-unicast
exit
interface "system"
no shutdown
exit
interface "sub-int-1"
passive
no shutdown
exit
interface "sub-int-2"
passive
no shutdown
exit
interface "toR1"
interface-type point-to-point
no shutdown
exit
no shutdown
exit
The corresponding IPv4 RIB on router R1 (from Components of the Routed CO Model) lists the subscriber-interface subnets, not the individual subscriber host addresses.
A:R1# show router "Base" route-table ipv4
===============================================================================
Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
10.1.1.0/24 Remote ISIS 00h14m11s 15
192.168.12.1 20
10.1.2.0/24 Remote ISIS 00h14m11s 15
192.168.12.1 20
10.2.1.0/24 Remote ISIS 00h14m05s 15
192.168.12.1 20
10.2.2.0/24 Remote ISIS 00h14m05s 15
192.168.12.1 20
192.0.2.75/32 Remote ISIS 00h14m17s 15
192.168.12.1 10
192.0.2.76/32 Local Local 62d21h22m 0
system 0
192.168.12.0/24 Local Local 05d04h43m 0
toBNG 0
-------------------------------------------------------------------------------
No. of Routes: 7
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
A:R1#
The corresponding IPv6 RIB on router R1 lists the subscriber-interface prefixes, not the individual subscriber host addresses/prefixes.
A:R1# show router "Base" route-table ipv6
===============================================================================
IPv6 Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
2001:DB8::75/128 Remote ISIS 00h04m25s 15
FE80::E84B:FFFF:FE00:0-"toBNG" 10
2001:DB8::76/128 Local Local 02d05h54m 0
system 0
2001:DB8:101::/48 Remote ISIS 00h04m25s 15
FE80::E84B:FFFF:FE00:0-"toBNG" 20
2001:DB8:102::/48 Remote ISIS 00h04m25s 15
FE80::E84B:FFFF:FE00:0-"toBNG" 20
2001:DB8:201::/48 Remote ISIS 00h04m25s 15
FE80::E84B:FFFF:FE00:0-"toBNG" 20
2001:DB8:202::/48 Remote ISIS 00h04m25s 15
FE80::E84B:FFFF:FE00:0-"toBNG" 20
2001:DEAD::/64 Local Local 01h42m18s 0
toBNG 0
-------------------------------------------------------------------------------
No. of Routes: 7
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
A:R1#
Alternatively the same result can be achieved with OSPF/OSPFv3.
Option 2 – Export Policy (from protocol direct)
The key properties for the second option are:
Subscriber interface subnets and prefixes are distributed into the network by applying an export policy.
It is most typically used in combination with BGP based route distribution.
It works with the numbered model only.
The following export policy is used for this example.
configure
router
policy-options
policy-statement "local-subnets-out"
entry 10
from
protocol direct
exit
action accept
exit
exit
exit
In this option the BNG relies on BGP using the policy local-subnets-out as an export policy. The neighbor address is the IPv4 system address of router R1.
configure
router
autonomous-system 65536
bgp
group "grp-1"
family ipv4 ipv6
export "local-subnets-out"
peer-as 65536
neighbor 192.0.2.76
advertise-label ipv6
exit
exit
no shutdown
exit
The following command shows the IPv4 routes advertised by applying the local-subnets-out policy. The subscriber interface subnets are advertised, as are some other local subnets.
*A:BNG# show router bgp neighbor 192.0.2.76 advertised-routes ipv4
===============================================================================
BGP Router ID:192.0.2.75 AS:65536 Local AS:65536
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
Origin codes : i - IGP, e - EGP, ? - incomplete, > - best, b - backup
===============================================================================
BGP IPv4 Routes
===============================================================================
Flag Network LocalPref MED
Nexthop Path-Id Label
As-Path
-------------------------------------------------------------------------------
i 10.1.1.0/24 100 None
192.0.2.75 None -
No As-Path
i 10.1.2.0/24 100 None
192.0.2.75 None -
No As-Path
i 10.2.1.0/24 100 None
192.0.2.75 None -
No As-Path
i 10.2.2.0/24 100 None
192.0.2.75 None -
No As-Path
i 10.11.11.1/32 100 None
192.0.2.75 None -
No As-Path
i 192.0.2.75/32 100 None
192.0.2.75 None -
No As-Path
i 192.168.12.0/24 100 None
192.0.2.75 None -
No As-Path
i 192.168.202.0/24 100 None
192.0.2.75 None -
No As-Path
-------------------------------------------------------------------------------
Routes : 8
===============================================================================
*A:BNG#
The same applies for IPv6.
*A:BNG# show router bgp neighbor 192.0.2.76 advertised-routes ipv6
===============================================================================
BGP Router ID:192.0.2.75 AS:65536 Local AS:65536
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
Origin codes : i - IGP, e - EGP, ? - incomplete, > - best, b - backup
===============================================================================
BGP IPv6 Routes
===============================================================================
Flag Network LocalPref MED
Nexthop Path-Id Label
As-Path
-------------------------------------------------------------------------------
i 2001:DB8::11/128 100 None
::FFFF:C000:24B None 2
No As-Path
i 2001:DB8::75/128 100 None
::FFFF:C000:24B None 2
No As-Path
i 2001:DB8:101::/48 100 None
::FFFF:C000:24B None 2
No As-Path
i 2001:DB8:102::/48 100 None
::FFFF:C000:24B None 2
No As-Path
i 2001:DB8:201::/48 100 None
::FFFF:C000:24B None 2
No As-Path
i 2001:DB8:202::/48 100 None
::FFFF:C000:24B None 2
No As-Path
i 2001:DEAD::/64 100 None
::FFFF:C000:24B None 2
No As-Path
-------------------------------------------------------------------------------
Routes : 7
===============================================================================
*A:BNG#
The corresponding IPv4 RIB on router R1 lists the subscriber-interface subnets, not the individual subscriber host addresses. Notice the list also includes other routes local to the BNG.
*A:R1# show router "Base" route-table ipv4
===============================================================================
Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
10.1.1.0/24 Remote BGP 00h13m34s 170
192.168.12.1 0
10.1.2.0/24 Remote BGP 00h13m34s 170
192.168.12.1 0
10.2.1.0/24 Remote BGP 00h13m34s 170
192.168.12.1 0
10.2.2.0/24 Remote BGP 00h13m34s 170
192.168.12.1 0
10.11.11.1/32 Remote BGP 00h13m34s 170
192.168.12.1 0
192.0.2.75/32 Remote ISIS 00h15m38s 15
192.168.12.1 10
192.0.2.76/32 Local Local 03h11m54s 0
system 0
192.168.12.0/24 Local Local 03h11m25s 0
toBNG 0
192.168.202.0/24 Remote BGP 00h13m34s 170
192.168.12.1 0
-------------------------------------------------------------------------------
No. of Routes: 9
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:R1#
The corresponding IPv6 RIB on router R1 lists the subscriber-interface prefixes, not the individual subscriber host addresses/prefixes. They are tunneled through the IPv4 core.
*A:R1# show router "Base" route-table ipv6
===============================================================================
IPv6 Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
2001:DB8::11/128 Remote BGP 00h00m49s 170
192.0.2.75 (tunneled) 0
2001:DB8::75/128 Remote ISIS 00h54m05s 15
FE80::E84B:FFFF:FE00:0-"toBNG" 10
2001:DB8::76/128 Local Local 05h18m12s 0
system 0
2001:DB8:101::/48 Remote BGP 00h00m49s 170
192.0.2.75 (tunneled) 0
2001:DB8:102::/48 Remote BGP 00h00m49s 170
192.0.2.75 (tunneled) 0
2001:DB8:201::/48 Remote BGP 00h00m49s 170
192.0.2.75 (tunneled) 0
2001:DB8:202::/48 Remote BGP 00h00m49s 170
192.0.2.75 (tunneled) 0
2001:DEAD::/64 Local Local 05h17m42s 0
toBNG 0
-------------------------------------------------------------------------------
No. of Routes: 8
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
*A:R1# #
The same export policy can be used in combination with IGP based route distribution. However, when IGP based route distribution is needed option 1 is the preferred method.
Option 3 – Export Protocol (from protocol sub-mgmt)
The key properties for the third option are:
Host addresses and prefixes are distributed into the network by applying an export policy.
It is most typically used in combination with BGP based route distribution, as IGP based route distribution does not scale for a large number of subscribers.
It is most typically used for the unnumbered model, and in some cases for the numbered model.
The following export policy is used for this option.
configure
router
policy-options
policy-statement "subsc-hosts-out"
entry 10
from
protocol sub-mgmt
exit
action accept
exit
exit
exit
In this option the BNG relies on BGP using the policy subsc-hosts-out as an export policy.
configure
router
autonomous-system 65536
bgp
group "grp-1"
family ipv4 ipv6
export "subsc-hosts-out"
peer-as 65536
neighbor 192.0.2.76
advertise-label ipv6
exit
exit
no shutdown
exit
The following command shows the IPv4 routes advertised by applying the subsc-hosts-out policy. Now the subscriber host addresses are advertised individually.
*A:BNG# show router bgp neighbor 192.0.2.76 advertised-routes ipv4
===============================================================================
BGP Router ID:192.0.2.75 AS:65536 Local AS:65536
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
Origin codes : i - IGP, e - EGP, ? - incomplete, > - best, b - backup
===============================================================================
BGP IPv4 Routes
===============================================================================
Flag Network LocalPref MED
Nexthop Path-Id Label
As-Path
-------------------------------------------------------------------------------
? 10.1.1.101/32 100 0
192.0.2.75 None -
No As-Path
? 10.1.1.102/32 100 0
192.0.2.75 None -
No As-Path
? 10.2.2.1/32 100 0
192.0.2.75 None -
No As-Path
? 10.2.2.2/32 100 0
192.0.2.75 None -
No As-Path
-------------------------------------------------------------------------------
Routes : 4
===============================================================================
*A:BNG#
For IPv6, the host addresses and prefixes are advertised.
*A:BNG# show router bgp neighbor 192.0.2.76 advertised-routes ipv6
===============================================================================
BGP Router ID:192.0.2.75 AS:65536 Local AS:65536
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
Origin codes : i - IGP, e - EGP, ? - incomplete, > - best, b - backup
===============================================================================
BGP IPv6 Routes
===============================================================================
Flag Network LocalPref MED
Nexthop Path-Id Label
As-Path
-------------------------------------------------------------------------------
? 2001:DB8:101::1/128 100 0
::FFFF:C000:24B None 2
No As-Path
? 2001:DB8:101:1::1/128 100 0
::FFFF:C000:24B None 2
No As-Path
? 2001:DB8:102::/56 100 0
::FFFF:C000:24B None 2
No As-Path
? 2001:DB8:102:100::/56 100 0
::FFFF:C000:24B None 2
No As-Path
-------------------------------------------------------------------------------
Routes : 4
===============================================================================
*A:BNG#
The corresponding IPv4 RIB on router R1 looks as follows. Notice the individual host addresses do appear.
A:R1# show router route-table ipv4
===============================================================================
Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
10.1.1.101/32 Remote BGP 00h40m49s 170
192.168.12.1 0
10.1.1.102/32 Remote BGP 00h19m53s 170
192.168.12.1 0
10.2.2.1/32 Remote BGP 00h44m49s 170
192.168.12.1 0
10.2.2.2/32 Remote BGP 00h44m17s 170
192.168.12.1 0
192.0.2.75/32 Remote ISIS 00h59m41s 15
192.168.12.1 10
192.0.2.76/32 Local Local 01h22m11s 0
system 0
192.168.12.0/24 Local Local 01h21m42s 0
toBNG 0
-------------------------------------------------------------------------------
No. of Routes: 7
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
A:R1#
The corresponding IPv6 RIB on router R1 looks as follows. Notice the individual host addresses and prefixes are distributed in this case.
A:R1# show router route-table ipv6
===============================================================================
IPv6 Route Table (Router: Base)
===============================================================================
Dest Prefix[Flags] Type Proto Age Pref
Next Hop[Interface Name] Metric
-------------------------------------------------------------------------------
2001:DB8::76/128 Local Local 01h22m16s 0
system 0
2001:DB8:101::1/128 Remote BGP 00h36m40s 170
192.0.2.75 (tunneled) 0
2001:DB8:101:1::1/128 Remote BGP 00h36m40s 170
192.0.2.75 (tunneled) 0
2001:DB8:102::/56 Remote BGP 00h36m40s 170
192.0.2.75 (tunneled) 0
2001:DB8:102:100::/56 Remote BGP 00h36m40s 170
192.0.2.75 (tunneled) 0
2001:DEAD::/64 Local Local 01h21m47s 0
toBNG 0
-------------------------------------------------------------------------------
No. of Routes: 6
Flags: L = LFA nexthop available B = BGP backup route available
n = Number of times nexthop is repeated
===============================================================================
A:R1#
Conclusion
This example explains how to configure and use the Routed CO model. The subscriber and the group interfaces were configured for the numbered, unnumbered and hybrid scenario, showing the flexibility of the Routed CO model in terms of subnet/prefix assignment as well as the impact on the forwarding and the reachability to and from the subscriber hosts.