SR-TE Weighted ECMP for EVPN Layer 2 Services
This chapter provides information about Segment Routing with Traffic Engineering (SR-TE) Weighted Equal Cost Multipath (ECMP) for EVPN Layer 2 services.
Topics in this chapter include:
Applicability
The information and configuration in this chapter are based on SR OS Release 24.7.R2.
SR-TE Weighted ECMP for EVPN Layer 2 services is supported on FP4-based platforms in SR OS Release 22.7.R1 and later.
Overview
- the auto-bind-tunnel ecmp parameter: configure service epipe|vpls <service id> bgp-evpn mpls bgp <bgp instance number> auto-bind-tunnel ecmp <maximum number of auto bind tunnel ECMP routes>
- the auto-bind-tunnel weighted-ecmp parameter: configure service epipe|vpls <service id> bgp-evpn mpls bgp <bgp instance number> auto-bind-tunnel weighted-ecmp
ECMP then refers to spraying data traffic across multiple named SR-TE tunnels (or RSVP-TE tunnels) within the same ECMP set.
- tunnel type preference parameter tunnel-table-pref,
applied from lowest to highest. Note: The tunnel-table-pref default value can be changed for all tunnel types, except for the SR policy tunnel type. Nokia recommends to avoid configuring different tunnel types with the same tunnel-table-pref value, because that can cause preference to be given to a tunnel type that has been introduced first in the history of SR OS: RSVP-TE, LDP, SR-OSPF/SR-OSPF3/SR-ISIS, SR-TE, regardless of the LSP metric and tunnel ID.Note: The SR policy tunnel type has a tunnel table preference that cannot be configured, because it always wins over other tunnel types when the service or routing context BGP route has a color attribute.
- When multiple tunnels exist for a selected tunnel type, the following
applies:
- RSVP-TE LSP <key={destination address, admin-tags}>: preference for tunnels with the lowest LSP metric, then the lowest tunnel ID.
- SR-TE LSP <key={destination address, admin-tags}>: preference for tunnels with the lowest LSP metric, then the lowest tunnel ID.
- LDP or BGP <key={destination address}>: one tunnel always exists (best route).
- SR-OSPF/SR-OSPF3/SR-ISIS <key={destination address, SR algorithm}> : preference for tunnels with the lowest IGP instance ID.
- MPLS forwarding policy <key={endpoint, admin-tags}>: one tunnel always exists (the lowest policy preference which is different from the parameter tunnel-table-pref).
- SR policy <key={endpoint, color}>: one tunnel always exists (the highest policy preference which is different from the parameter tunnel-table-pref).
Note: The preceding bullet list does not imply an order of tunnel type preference.
When multiple tunnels of the selected tunnel type are operational, data traffic is sprayed across them. The maximum number of tunnels of this type that can be used is configured with the auto-bind-tunnel ecmp parameter. When the number of SR-TE or RSVP-TE tunnels that are operational exceeds this maximum, only tunnels of the selected tunnel type (SR-TE LSP or RSVP-TE LSP) with the same lowest LSP metric can be part of the ECMP set. The LSP metric is configured with the LSP metric parameter: configure router "Base" mpls lsp <LSP name> metric <metric value>. When the number of tunnels in this ECMP set still exceeds the value configured in the auto-bind-tunnel ecmp parameter, the lowest tunnel ID tunnels are selected first.
normalised weight of an LSP =
configured weight of the LSP / (sum of the configured weights of all used LSPs in the retained ECMP set)
When the LSP load balancing weight parameter is not configured for at least one tunnel in the retained ECMP set, regular ECMP spraying across the tunnels in the retained ECMP set is used.
For shortest path tunnels, such as LDP, SR-OSPF, SR-OSPF3, SR-ISIS, and UDP tunnels, the maximum number of tunnels in the ECMP set is configured in the ECMP parameter: configure router "Base" ecmp <maximum number of ECMP routes>.
Configuration
- cards, MDAs, ports
- router interfaces
- BGP for the EVPN address family
- IS-IS or OSPF or OSPF3, MPLS, RSVP, and LDP on the router interfaces. OSPF and OSPF3 are not used in this chapter.
- RSVP-TE, SR-TE, LDP, and SR-ISIS tunnels. UDP tunnels are not used in this chapter.
- an EVPN VPLS service on PE-1 and PE-4 that can make use of these tunnels.
Router configuration
To allow multiple different MPLS paths from PE-1 to PE-4, four router interfaces are configured between PE-1 and PE-2, and between PE-1 and PE-3.
# on PE-1:
configure router "Base"
interface "int-PE-1-PE-2-1"
address 192.168.12.1/30
port 1/1/c1/1
no shutdown
exit
interface "int-PE-1-PE-2-2"
address 192.168.12.5/30
port 1/1/c3/1
no shutdown
exit
interface "int-PE-1-PE-2-3"
address 192.168.12.9/30
port 1/1/c5/1
no shutdown
exit
interface "int-PE-1-PE-2-4"
address 192.168.12.13/30
port 1/1/c7/1
no shutdown
exit
interface "int-PE-1-PE-3-1"
address 192.168.13.1/30
port 1/1/c2/1
no shutdown
exit
interface "int-PE-1-PE-3-2"
address 192.168.13.5/30
port 1/1/c4/1
no shutdown
exit
interface "int-PE-1-PE-3-3"
address 192.168.13.9/30
port 1/1/c6/1
no shutdown
exit
interface "int-PE-1-PE-3-4"
address 192.168.13.13/30
port 1/1/c8/1
no shutdown
exit
interface "system"
address 192.0.2.1/32
no shutdown
exit
autonomous-system 64500
bgp
group "iBGP"
family evpn
peer-as 64500
neighbor 192.0.2.2
exit
neighbor 192.0.2.3
exit
neighbor 192.0.2.4
exit
exit
no shutdown
exit
mpls-labels
sr-labels start 32000 end 32999
exit
isis 0
area-id 49.0001
traffic-engineering
advertise-passive-only
advertise-router-capability as
no ipv6-multicast-routing
segment-routing
prefix-sid-range global
no shutdown
exit
interface "system"
ipv4-node-sid label 32001
passive
no shutdown
exit
interface "int-PE-1-PE-2-1"
interface-type point-to-point
no shutdown
exit
interface "int-PE-1-PE-2-2"
interface-type point-to-point
no shutdown
exit
interface "int-PE-1-PE-2-3"
interface-type point-to-point
no shutdown
exit
interface "int-PE-1-PE-2-4"
interface-type point-to-point
no shutdown
exit
interface "int-PE-1-PE-3-1"
interface-type point-to-point
no shutdown
exit
interface "int-PE-1-PE-3-2"
interface-type point-to-point
no shutdown
exit
interface "int-PE-1-PE-3-3"
interface-type point-to-point
no shutdown
exit
interface "int-PE-1-PE-3-4"
interface-type point-to-point
no shutdown
exit
no shutdown
exit
mpls
interface "system"
no shutdown
exit
interface "int-PE-1-PE-2-1"
no shutdown
exit
interface "int-PE-1-PE-2-2"
no shutdown
exit
interface "int-PE-1-PE-2-3"
no shutdown
exit
interface "int-PE-1-PE-2-4"
no shutdown
exit
interface "int-PE-1-PE-3-1"
no shutdown
exit
interface "int-PE-1-PE-3-2"
no shutdown
exit
interface "int-PE-1-PE-3-3"
no shutdown
exit
interface "int-PE-1-PE-3-4"
no shutdown
exit
exit
rsvp
interface "system"
no shutdown
exit
interface "int-PE-1-PE-2-1"
no shutdown
exit
interface "int-PE-1-PE-2-2"
no shutdown
exit
interface "int-PE-1-PE-2-3"
no shutdown
exit
interface "int-PE-1-PE-2-4"
no shutdown
exit
interface "int-PE-1-PE-3-1"
no shutdown
exit
interface "int-PE-1-PE-3-2"
no shutdown
exit
interface "int-PE-1-PE-3-3"
no shutdown
exit
interface "int-PE-1-PE-3-4"
no shutdown
exit
no shutdown
exit
ldp
interface-parameters
interface "int-PE-1-PE-2-1" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
interface "int-PE-1-PE-2-2" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
interface "int-PE-1-PE-2-3" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
interface "int-PE-1-PE-2-4" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
interface "int-PE-1-PE-3-1" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
interface "int-PE-1-PE-3-2" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
interface "int-PE-1-PE-3-3" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
interface "int-PE-1-PE-3-4" dual-stack
ipv4
no shutdown
exit
no shutdown
exit
exit
targeted-session
exit
no shutdown
exit
The configuration of PE-2, PE-3, and PE-4 is similar.# on PE-1:
configure router "Base" mpls
path "path-1-PE-1-2-4"
hop 1 192.168.12.2 strict
hop 2 192.0.2.4 loose
no shutdown
exit
path "path-2-PE-1-3-4"
hop 1 192.168.13.2 strict
hop 2 192.0.2.4 loose
no shutdown
exit
path "path-3-PE-1-2-4"
hop 1 192.168.12.6 strict
hop 2 192.0.2.4 loose
no shutdown
exit
path "path-4-PE-1-3-4"
hop 1 192.168.13.6 strict
hop 2 192.0.2.4 loose
no shutdown
exit
path "path-5-PE-1-2-4"
hop 1 192.168.12.10 strict
hop 2 192.0.2.4 loose
no shutdown
exit
path "path-6-PE-1-3-4"
hop 1 192.168.13.10 strict
hop 2 192.0.2.4 loose
no shutdown
exit
path "path-7-PE-1-2-4"
hop 1 192.168.12.14 strict
hop 2 192.0.2.4 loose
no shutdown
exit
path "path-8-PE-1-3-4"
hop 1 192.168.13.14 strict
hop 2 192.0.2.4 loose
no shutdown
exit
Path | Via Interface |
---|---|
"path-1-PE-1-2-4" | "int-PE-1-PE-2-1" |
"path-2-PE-1-3-4" | "int-PE-1-PE-3-1" |
"path-3-PE-1-2-4" | "int-PE-1-PE-2-2" |
"path-4-PE-1-3-4" | "int-PE-1-PE-3-2" |
"path-5-PE-1-2-4" | "int-PE-1-PE-2-3" |
"path-6-PE-1-3-4" | "int-PE-1-PE-3-3" |
"path-7-PE-1-2-4" | "int-PE-1-PE-2-4" |
"path-8-PE-1-3-4" | "int-PE-1-PE-3-4" |
# on PE-1:
configure router "Base" mpls
# SR-TE LSPs
lsp "lsp-sr-te-1-PE-1-2-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 10
load-balancing-weight 60
primary "path-1-PE-1-2-4"
exit
no shutdown
exit
lsp "lsp-sr-te-2-PE-1-3-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 10
load-balancing-weight 120
primary "path-2-PE-1-3-4"
exit
no shutdown
exit
lsp "lsp-sr-te-3-PE-1-2-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 8
load-balancing-weight 1
primary "path-3-PE-1-2-4"
exit
no shutdown
exit
lsp "lsp-sr-te-4-PE-1-3-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 10
load-balancing-weight 180
primary "path-4-PE-1-3-4"
exit
no shutdown
exit
lsp "lsp-sr-te-5-PE-1-2-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 10
load-balancing-weight 120
primary "path-5-PE-1-2-4"
exit
no shutdown
exit
lsp "lsp-sr-te-6-PE-1-3-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 8
load-balancing-weight 3
primary "path-6-PE-1-3-4"
exit
no shutdown
exit
lsp "lsp-sr-te-7-PE-1-2-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 10
load-balancing-weight 60
primary "path-7-PE-1-2-4"
exit
no shutdown
exit
lsp "lsp-sr-te-8-PE-1-3-4" sr-te
to 192.0.2.4
path-computation-method local-cspf
metric 11
load-balancing-weight 5
primary "path-8-PE-1-3-4"
exit
no shutdown
exit
# RSVP-TE LSPs
lsp "lsp-rsvp-te-1-PE-1-2-4"
to 192.0.2.4
path-computation-method local-cspf
metric 12
load-balancing-weight 4
primary "path-1-PE-1-2-4"
exit
no shutdown
exit
lsp "lsp-rsvp-te-2-PE-1-3-4"
to 192.0.2.4
path-computation-method local-cspf
metric 12
load-balancing-weight 3
primary "path-2-PE-1-3-4"
exit
no shutdown
exit
lsp "lsp-rsvp-te-3-PE-1-2-4"
to 192.0.2.4
path-computation-method local-cspf
metric 14
load-balancing-weight 2
primary "path-3-PE-1-2-4"
exit
no shutdown
exit
lsp "lsp-rsvp-te-4-PE-1-3-4"
to 192.0.2.4
path-computation-method local-cspf
metric 12
load-balancing-weight 1
primary "path-4-PE-1-3-4"
exit
no shutdown
exit
# on PE-1:
configure router mpls lsp "lsp-sr-te-1-PE-1-2-4" metric ?
- metric <metric>
- no metric
<metric> : <0..16777215>
# on PE-1:
configure router mpls lsp "lsp-sr-te-1-PE-1-2-4" load-balancing-weight ?
- load-balancing-weight <weight>
- no load-balancing-weight
<weight> : [0..4294967295] Default - 0
LSP Name | LSP Type | LSP Tunnel ID | LSP Metric | LSP Load Balancing Weight | Primary Path |
---|---|---|---|---|---|
"lsp-sr-te-1-PE-1-2-4" | SR-TE | 655362 | 10 | 60 | "path-1-PE-1-2-4-" |
"lsp-sr-te-2-PE-1-3-4" | SR-TE | 655363 | 10 | 120 | "path-2-PE-1-3-4" |
"lsp-sr-te-3-PE-1-2-4" | SR-TE | 655364 | 12 | 1 | "path-3-PE-1-2-4" |
"lsp-sr-te-4-PE-1-3-4" | SR-TE | 655365 | 10 | 180 | "path-4-PE-1-3-4" |
"lsp-sr-te-5-PE-1-2-4" | SR-TE | 655366 | 10 | 120 | "path-5-PE-1-2-4" |
"lsp-sr-te-6-PE-1-3-4" | SR-TE | 655367 | 12 | 3 | "path-6-PE-1-3-4" |
"lsp-sr-te-7-PE-1-2-4" | SR-TE | 655368 | 10 | 60 | "path-7-PE-1-2-4" |
"lsp-sr-te-8-PE-1-3-4" | SR-TE | 655369 | 11 | 5 | "path-8-PE-1-3-4" |
"lsp-rsvp-te-1-PE-1-2-4" | RSVP-TE | 1 | 12 | 4 | "path-1-PE-1-2-4" |
"lsp-rsvp-te-2-PE-1-3-4" | RSVP-TE | 2 | 12 | 3 | "path-2-PE-1-3-4" |
"lsp-rsvp-te-3-PE-1-2-4" | RSVP-TE | 3 | 14 | 2 | "path-3-PE-1-2-4" |
"lsp-rsvp-te-4-PE-1-3-4" | RSVP-TE | 4 | 12 | 1 | "path-4-PE-1-3-4" |
While not strictly needed, similar MPLS tunnels are configured on PE-4.
The SR OS automatically generates the SR-TE tunnel IDs (and RSVP-TE tunnel IDs) in the order in which the SR-TE tunnels (and RSVP-TE tunnels) are added. The SR OS also automatically generates the tunnel IDs for the other tunnel protocols.
*A:PE-1# show router mpls path lsp-binding
===============================================================================
MPLS Path: Bindings
===============================================================================
Path Name Opr LSP Name Binding
-------------------------------------------------------------------------------
path-1-PE-1-2-4 Up lsp-rsvp-te-1-PE-1-2-4 Primary
Up lsp-sr-te-1-PE-1-2-4 Primary
path-2-PE-1-3-4 Up lsp-rsvp-te-2-PE-1-3-4 Primary
Up lsp-sr-te-2-PE-1-3-4 Primary
path-3-PE-1-2-4 Up lsp-rsvp-te-3-PE-1-2-4 Primary
Up lsp-sr-te-3-PE-1-2-4 Primary
path-4-PE-1-3-4 Up lsp-rsvp-te-4-PE-1-3-4 Primary
Up lsp-sr-te-4-PE-1-3-4 Primary
path-5-PE-1-2-4 Up lsp-sr-te-5-PE-1-2-4 Primary
path-6-PE-1-3-4 Up lsp-sr-te-6-PE-1-3-4 Primary
path-7-PE-1-2-4 Up lsp-sr-te-7-PE-1-2-4 Primary
path-8-PE-1-3-4 Up lsp-sr-te-8-PE-1-3-4 Primary
-------------------------------------------------------------------------------
Paths : 8
===============================================================================
Service configuration
# on PE-1:
configure service vpls 14 name "VPLS 14" customer 1 create
bgp
exit
bgp-evpn
evi 14
mpls bgp 1
ingress-replication-bum-label
auto-bind-tunnel
resolution-filter
rsvp
ldp
sr-isis
sr-te
udp
exit
resolution filter
ecmp 3
weighted-ecmp
exit
no shutdown
exit
exit
sap 1/1/c9/1:100 create
no shutdown
exit
no shutdown
# on PE-1:
configure service vpls "VPLS 14" bgp-evpn mpls bgp 1 auto-bind-tunnel resolution-filter ?
- resolution-filter
[no] bgp - Enable/disable setting BGP type for auto-bind-tunnel
[no] ldp - Enable/disable setting LDP type for auto-bind-tunnel
[no] mpls-fwd-policy - Enable/disable MPLS Forwarding Policy for auto-bind-tunnel
[no] rib-api - Enable/disable setting RIB-API type for auto-bind-tunnel
[no] rsvp - Enable/disable setting RSVP-TE type for auto-bind-tunnel
[no] sr-isis - Enable/disable setting SR-ISIS type for auto-bind-tunnel
[no] sr-ospf - Enable/disable setting SR-OSPF type for auto-bind-tunnel
[no] sr-ospf3 - Enable/disable setting SR-OSPFv3 type for auto-bind-tunnel
[no] sr-policy - Enable/disable setting SR-Policy type for auto-bind-tunnel
[no] sr-te - Enable/disable setting SR-TE type for auto-bind-tunnel
[no] udp - Enable/disable setting UDP type for auto-bind-tunnel
# on PE-1:
configure service vpls "VPLS 14" bgp-evpn mpls bgp 1 auto-bind-tunnel ecmp ?
- ecmp <max-ecmp-routes>
<max-ecmp-routes> : [1..32]: default 1
# on PE-1:
configure service vpls "VPLS 14" bgp-evpn mpls bgp 1 auto-bind-tunnel weighted-ecmp ?
- no weighted-ecmp
- weighted-ecmp
When ecmp 3 is configured, the EVPN
VPLS supports the establishment of a maximum of three RSVP-TE, SR-TE, LDP (,or
SR-OSPF, or SR-OSPF3), SR-ISIS (, or UDP) tunnels with per-LSP load balancing of
the data traffic from PE-1 to PE-4. This can be verified with the following
show
command:*A:PE-1# show service id 14 bgp-evpn
===============================================================================
BGP EVPN
===============================================================================
EVI : 14
Adv L2 Attributes : Disabled
Ignore Mtu Mismatch: Disabled
MAC/IP Routes
MAC Advertisement : Enabled Unknown MAC Route : Disabled
---snip---
===============================================================================
BGP EVPN MPLS Information
===============================================================================
Admin Status : Enabled Bgp Instance : 1
Force Vlan Fwding : Disabled
Force Qinq Fwding : none
Route NextHop Type : system-ipv4
Control Word : Disabled
Max Ecmp Routes : 1
Entropy Label : Disabled
Default Route Tag : none
Split Horizon Group: (Not Specified)
Ingress Rep BUM Lbl: Enabled
Ingress Ucast Lbl : 524273 Ingress Mcast Lbl : 524272
RestProtSrcMacAct : none
Evpn Mpls Encap : Enabled Evpn MplsoUdp : Disabled
Oper Group : (none)
MH Mode : network
Evi 3-byte Auto-RT : Disabled
Dyn Egr Lbl Limit : Disabled
Hash Label : Disabled
Local AC Ingr Lbl : <not-allocated>
BGP EVPN MPLS Auto Bind Tunnel Information
-------------------------------------------------------------------------------
Allow-Flex-Algo-FB : Disabled
Resolution : filter Strict Tnl Tag : Disabled
Max Ecmp Routes : 3
Filter Tunnel Types: ldp rsvp sr-isis sr-te udp
Weighted Ecmp : Enabled
===============================================================================
*A:PE-4# show service id 14 bgp-evpn
===============================================================================
BGP EVPN
===============================================================================
EVI : 14
Adv L2 Attributes : Disabled
Ignore Mtu Mismatch: Disabled
MAC/IP Routes
MAC Advertisement : Enabled Unknown MAC Route : Disabled
---snip---
===============================================================================
BGP EVPN MPLS Information
===============================================================================
Admin Status : Enabled Bgp Instance : 1
Force Vlan Fwding : Disabled
Force Qinq Fwding : none
Route NextHop Type : system-ipv4
Control Word : Disabled
Max Ecmp Routes : 1
Entropy Label : Disabled
Default Route Tag : none
Split Horizon Group: (Not Specified)
Ingress Rep BUM Lbl: Enabled
Ingress Ucast Lbl : 524277 Ingress Mcast Lbl : 524276
RestProtSrcMacAct : none
Evpn Mpls Encap : Enabled Evpn MplsoUdp : Disabled
Oper Group : (none)
MH Mode : network
Evi 3-byte Auto-RT : Disabled
Dyn Egr Lbl Limit : Disabled
Hash Label : Disabled
Local AC Ingr Lbl : <not-allocated>
BGP EVPN MPLS Auto Bind Tunnel Information
-------------------------------------------------------------------------------
Allow-Flex-Algo-FB : Disabled
Resolution : filter Strict Tnl Tag : Disabled
Max Ecmp Routes : 2
Filter Tunnel Types: ldp rsvp sr-isis sr-te udp
Weighted Ecmp : Disabled
===============================================================================
Use cases
- Tunnel selection with preference for SR-TE
- LSP load balancing weights configured on all selected SR-TE tunnels
- LSP load balancing weight not configured on at least one selected SR-TE tunnel
- Maximum number of tunnels increased but below the possible number of tunnels
- Maximum number of tunnels exceeding the possible number of tunnels
- Minimum LSP metric values configured on SR-TE tunnels with a higher tunnel ID
- SR-TE tunnel type no longer supported
- Also RSVP-TE tunnel type no longer supported
- Also LDP tunnel type no longer supported
To verify the operation in these use cases, UDP data traffic is launched at a rate of 2000 packets per second from a test source connected to PE-1 to a test destination connected to PE-4.
Tunnel selection with preference for SR-TE
Tunnel Protocol | Preference |
---|---|
RSVP-TE | 7 |
SR-TE | 8 |
LDP | 9 |
SR-OSPF/SR-OSPF3 | 10 |
SR-ISIS | 11 |
The tunnel-table-preference for different tunnel protocols can be configured with the following commands:
# on PE-1:
configure router mpls tunnel-table-pref ?
- tunnel-table-pref
[no] rsvp-te - Configure Tunnel Table Preference for RSVP-TE type LSPs
[no] sr-te - Configure Tunnel Table Preference for SR-TE type LSPs
configure router mpls tunnel-table-pref rsvp-te ?
- rsvp-te <[1..255]>
- no rsvp-te
configure router mpls tunnel-table-pref sr-te ?
- sr-te <[1..255]>
- no sr-te
# on PE-1:
configure router ldp tunnel-table-pref ?
- no tunnel-table-pref
- tunnel-table-pref <preference>
<preference> : [1..255]
# on PE-1:
configure router ospf segment-routing tunnel-table-pref ?
- no tunnel-table-pref
- tunnel-table-pref <[1..255]>
# on PE-1:
configure router ospf3 segment-routing tunnel-table-pref ?
- no tunnel-table-pref
- tunnel-table-pref <[1..255]>
# on PE-1:
configure router isis segment-routing tunnel-table-pref ?
- no tunnel-table-pref
- tunnel-table-pref <[1..255]>
The Tunnel table preferences to prefer SR-TE table shows the modified tunnel preference table with SR-TE as the preferred tunnel type.
# on PE-1:
configure router "Base" mpls tunnel-table-pref
sr-te 1
Tunnel Protocol | Preference |
---|---|
SR-TE | 8 → 1 |
RSVP-TE | 7 |
LDP | 9 |
SR-OSPF/SR-OSPF3 | 10 |
SR-ISIS | 11 |
LSP load balancing weights configured on all selected SR-TE tunnels
As can be derived from the Configured MPLS Tunnels table, there are eight possible SR-TE tunnels, of which only five have the lowest LSP metric value of 10, leading to Configured SR-TE Tunnels. This can be verified with the output of the following show command, that also contains the configured RSVP-TE tunnels, and the automatically generated LDP and SR-ISIS tunnels:
*A:PE-1# show router tunnel-table 192.0.2.4/32
===============================================================================
IPv4 Tunnel Table (Router: Base)
===============================================================================
Destination Owner Encap TunnelId Pref Nexthop Metric
Color
-------------------------------------------------------------------------------
192.0.2.4/32 sr-te MPLS 655362 1 192.168.12.2 10
192.0.2.4/32 sr-te MPLS 655363 1 192.168.13.2 10
192.0.2.4/32 sr-te MPLS 655365 1 192.168.13.6 10
192.0.2.4/32 sr-te MPLS 655366 1 192.168.12.10 10
192.0.2.4/32 sr-te MPLS 655368 1 192.168.12.14 10
192.0.2.4/32 sr-te MPLS 655369 1 192.168.13.14 11
192.0.2.4/32 sr-te MPLS 655364 1 192.168.12.6 12
192.0.2.4/32 sr-te MPLS 655367 1 192.168.13.10 12
192.0.2.4/32 rsvp MPLS 1 7 192.168.12.2 12
192.0.2.4/32 rsvp MPLS 2 7 192.168.13.2 12
192.0.2.4/32 rsvp MPLS 4 7 192.168.13.6 12
192.0.2.4/32 rsvp MPLS 3 7 192.168.12.6 14
192.0.2.4/32 ldp MPLS 65539 9 192.168.12.2 20
192.0.2.4/32 isis (0) MPLS 524299 11 192.168.12.2 20
-------------------------------------------------------------------------------
---snip---
===============================================================================
LSP Name | LSP Type | LSP Tunnel ID | LSP Metric | LSP Load Balancing Weight | Primary Path |
---|---|---|---|---|---|
"lsp-sr-te-1-PE-1-2-4" | SR-TE | 655362 | 10 | 60 | "path-1-PE-1-2-4" |
"lsp-sr-te-2-PE-1-3-4" | SR-TE | 655363 | 10 | 120 | "path-2-PE-1-3-4" |
"lsp-sr-te-4-PE-1-3-4" | SR-TE | 655365 | 10 | 180 | "path-4-PE-1-3-4" |
"lsp-sr-te-5-PE-1-2-4" | SR-TE | 655366 | 10 | 120 | "path-5-PE-1-2-4" |
"lsp-sr-te-7-PE-1-2-4" | SR-TE | 655368 | 10 | 60 | "path-7-PE-1-2-4" |
- "lsp-sr-te-1-PE-1-2-4" carries 60/(60+120+180)=60/360=16.67% of the data traffic via "path-1-PE-1-2-4"
- "lsp-sr-te-2-PE-1-3-4" carries 120/360=33.33% of the data traffic via "path-2-PE-1-3-4"
- "lsp-sr-te-4-PE-1-3-4" carries 180/360=50% of the data traffic via "path-4-PE-1-3-4"
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 1176 1 0 0.00
O 391176 336 0 0.00
1/1/c2/1 I 824 1 0 0.00
O 783064 670 0 0.00
1/1/c3/1 I 488 0 0 0.00
O 504 0 0 0.00
1/1/c4/1 I 168 0 0 0.00
O 1164136 997 0 0.00
---snip---
1/1/c9/1 I 2048000 2000 0 0.00
O 0 0 0 0.00
=====================================================================
*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 sr-te:655362 524276 Up bum 0
---snip---
LSP load balancing weight not configured on at least one selected SR-TE tunnel
# on PE-1:
configure router "Base" mpls lsp "lsp-sr-te-4-PE-1-3-4"
no load-balancing-weight
- "lsp-sr-te-1-PE-1-2-4" carries 33.33% of the data traffic via "path-1-PE-1-2-4"
- "lsp-sr-te-2-PE-1-3-4" carries 33.33% of the data traffic via "path-2-PE-1-3-4"
- "lsp-sr-te-4-PE-1-3-4" carries 33.33% of the data traffic via "path-4-PE-1-3-4"
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 1120 2 0 0.00
O 791328 678 0 0.00
1/1/c2/1 I 888 2 0 0.00
O 766808 657 0 0.00
1/1/c3/1 I 1016 1 0 0.00
O 1016 1 0 0.00
1/1/c4/1 I 1016 1 0 0.00
O 780592 668 0 0.00
---snip---
1/1/c9/1 I 2048000 2000 0 0.00
O 0 0 0 0.00
=====================================================================
*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 sr-te:655362 524276 Up bum 0
---snip---
Maximum number of tunnels increased but below the possible number of tunnels
# on PE-1:
configure router "Base" mpls lsp "lsp-sr-te-4-PE-1-3-4"
load-balancing-weight 180
# on PE-1:
configure service vpls 14 bgp-evpn mpls bgp 1 auto-bind-tunnel
ecmp 4
- "lsp-sr-te-1-PE-1-2-4" carries 60/(60+120+180+120)=60/480=12.5% of the data traffic via "path-1-PE-1-2-4"
- "lsp-sr-te-2-PE-1-3-4" carries 120/480=25% of the data traffic via "path-2-PE-1-3-4"
- "lsp-sr-te-4-PE-1-3-4" carries 180/480=37.5% of the data traffic via "path-4-PE-1-3-4"
- "lsp-sr-te-5-PE-1-2-4" carries 120/480=25% of the data traffic via "path-5-PE-1-2-4"
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 1544 3 0 0.00
O 291208 251 0 0.00
1/1/c2/1 I 1904 3 0 0.00
O 586000 502 0 0.00
1/1/c3/1 I 688 1 0 0.00
O 1016 1 0 0.00
1/1/c4/1 I 1336 1 0 0.00
O 877608 752 0 0.00
1/1/c5/1 I 368 0 0 0.00
O 587480 504 0 0.00
---snip---
1/1/c9/1 I 2048000 2000 0 0.00
O 0 0 0 0.00
=====================================================================
The following show command confirms that the selected tunnel type is indeed SR-TE, with (first) the lowest LSP metric (as from Configured MPLS Tunnels) and (second) the lowest tunnel ID.
*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 sr-te:655362 524276 Up bum 0
---snip---
Maximum number of tunnels exceeding the possible number of tunnels
# on PE-1:
configure service vpls 14 bgp-evpn mpls bgp 1 auto-bind-tunnel
ecmp 20
- "lsp-sr-te-1-PE-1-2-4" carries 60/(60+120+180+120+60)=60/540=11.11% of the data traffic via "path-1-PE-1-2-4"
- "lsp-sr-te-2-PE-1-3-4" carries 120/540=22.22% of the data traffic via "path-2-PE-1-3-4"
- "lsp-sr-te-4-PE-1-3-4" carries 180/540=33.33% of the data traffic via "path-4-PE-1-3-4"
- "lsp-sr-te-5-PE-1-2-4" carries 120/540=22.22% of the data traffic via "path-5-PE-1-2-4"
- "lsp-sr-te-7-PE-1-2-4" carries 60/540=11.11% of the data traffic via "path-7-PE-1-2-4"
PE-1 receives 2000 packets per second on port 1/1/c9/1 and sends out 221 packets per second on 1/1/c1/1 (~11.11%; "lsp-sr-te-1-PE-1-2-4"), 438 packets per second on 1/1/c2/1 (~22.22%; "lsp-sr-te-2-PE-1-3-4"), 663 packets per second on 1/1/c4/1 (~33.33%; "lsp-sr-te-4-PE-1-3-4"), 455 packets per second on 1/1/c5/1 (~22.22%; "lsp-sr-te-5-PE-1-2-4"), and 231 packets per second on 1/1/c7/1 (~11.11%; "lsp-sr-te-7-PE-1-2-4").
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 1208 2 0 0.00
O 256488 221 0 0.00
1/1/c2/1 I 1632 2 0 0.00
O 510928 438 0 0.00
1/1/c3/1 I 1016 1 0 0.00
O 368 0 0 0.00
1/1/c4/1 I 1016 1 0 0.00
O 773912 663 0 0.00
1/1/c5/1 I 1016 1 0 0.00
O 531608 455 0 0.00
1/1/c6/1 I 1168 1 0 0.00
O 528 1 0 0.00
1/1/c7/1 I 528 1 0 0.00
O 269808 231 0 0.00
---snip---
1/1/c9/1 I 2048344 2000 0 0.00
O 0 0 0 0.00
=====================================================================
*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 sr-te:655362 524276 Up bum 0
---snip---
Minimum LSP metric values configured on SR-TE tunnels with a higher tunnel ID
# on PE-1:
configure router "Base" mpls
lsp "lsp-sr-te-3-PE-1-2-4"
metric 8
exit
lsp "lsp-sr-te-6-PE-1-3-4"
metric 8
exit
*A:PE-1# show router tunnel-table 192.0.2.4/32
===============================================================================
IPv4 Tunnel Table (Router: Base)
===============================================================================
Destination Owner Encap TunnelId Pref Nexthop Metric
Color
-------------------------------------------------------------------------------
192.0.2.4/32 sr-te MPLS 655364 1 192.168.12.6 8
192.0.2.4/32 sr-te MPLS 655367 1 192.168.13.10 8
192.0.2.4/32 sr-te MPLS 655362 1 192.168.12.2 10
192.0.2.4/32 sr-te MPLS 655363 1 192.168.13.2 10
192.0.2.4/32 sr-te MPLS 655365 1 192.168.13.6 10
192.0.2.4/32 sr-te MPLS 655366 1 192.168.12.10 10
192.0.2.4/32 sr-te MPLS 655368 1 192.168.12.14 10
192.0.2.4/32 sr-te MPLS 655369 1 192.168.13.14 11
192.0.2.4/32 rsvp MPLS 1 7 192.168.12.2 12
192.0.2.4/32 rsvp MPLS 2 7 192.168.13.2 12
192.0.2.4/32 rsvp MPLS 4 7 192.168.13.6 12
192.0.2.4/32 rsvp MPLS 3 7 192.168.12.6 14
192.0.2.4/32 ldp MPLS 65539 9 192.168.12.2 20
192.0.2.4/32 isis (0) MPLS 524299 11 192.168.12.2 20
-------------------------------------------------------------------------------
---snip---
===============================================================================
LSP Name | LSP Type | LSP Tunnel ID | LSP Metric | LSP Load Balancing Weight | Primary Path |
---|---|---|---|---|---|
"lsp-sr-te-3-PE-1-2-4" | SR-TE | 655364 | 12 → 8 | 1 | "path-3-PE-1-2-4" |
"lsp-sr-te-6-PE-1-3-4" | SR-TE | 655367 | 12 → 8 | 3 | "path-6-PE-1-3-4" |
- "lsp-sr-te-3-PE-1-2-4" carries 1/(1+3)=1/4=25% of the data traffic via "path-3-PE-1-2-4"
- "lsp-sr-te-6-PE-1-3-4" carries 3/4=75% of the data traffic via "path-6-PE-1-3-4"
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 824 1 0 0.00
O 488 0 0 0.00
1/1/c2/1 I 824 1 0 0.00
O 1144 1 0 0.00
1/1/c3/1 I 488 0 0 0.00
O 580472 497 0 0.00
1/1/c4/1 I 504 0 0 0.00
O 824 1 0 0.00
1/1/c5/1 I 824 1 0 0.00
O 944 1 0 0.00
1/1/c6/1 I 656 1 0 0.00
O 1757008 1504 0 0.00
---snip---
1/1/c9/1 I 2048000 2000 0 0.00
O 0 0 0 0.00
=====================================================================
The
following show command confirms that the selected
tunnel type is indeed SR-TE, with (first) the lowest LSP metric (as from
Configured MPLS Tunnels) and (second) the
lowest tunnel ID.*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 sr-te:655364 524276 Up bum 0
---snip---
SR-TE tunnel type no longer supported
When the sr-te option is removed from the auto-bind-tunnel resolution-filter, RSVP-TE tunnels are preferred, in accordance with Tunnel table preferences to prefer SR-TE.
# on PE-1:
configure service vpls 14 bgp-evpn mpls bgp 1 auto-bind-tunnel resolution-filter
no sr-te
*A:PE-1# show router tunnel-table 192.0.2.4/32
===============================================================================
IPv4 Tunnel Table (Router: Base)
===============================================================================
Destination Owner Encap TunnelId Pref Nexthop Metric
Color
-------------------------------------------------------------------------------
192.0.2.4/32 sr-te MPLS 655364 1 192.168.12.6 8
192.0.2.4/32 sr-te MPLS 655367 1 192.168.13.10 8
192.0.2.4/32 sr-te MPLS 655362 1 192.168.12.2 10
192.0.2.4/32 sr-te MPLS 655363 1 192.168.13.2 10
192.0.2.4/32 sr-te MPLS 655365 1 192.168.13.6 10
192.0.2.4/32 sr-te MPLS 655366 1 192.168.12.10 10
192.0.2.4/32 sr-te MPLS 655368 1 192.168.12.14 10
192.0.2.4/32 sr-te MPLS 655369 1 192.168.13.14 11
192.0.2.4/32 rsvp MPLS 1 7 192.168.12.2 12
192.0.2.4/32 rsvp MPLS 2 7 192.168.13.2 12
192.0.2.4/32 rsvp MPLS 4 7 192.168.13.6 12
192.0.2.4/32 rsvp MPLS 3 7 192.168.12.6 14
192.0.2.4/32 ldp MPLS 65539 9 192.168.12.2 20
192.0.2.4/32 isis (0) MPLS 524299 11 192.168.12.2 20
-------------------------------------------------------------------------------
---snip---
===============================================================================
LSP Name | LSP Type | LSP Tunnel ID | LSP Metric | LSP Load Balancing Weight | Primary Path |
---|---|---|---|---|---|
"lsp-rsvp-te-1-PE-1-2-4" | RSVP-TE | 1 | 12 | 4 | "path-1-PE-1-2-4" |
"lsp-rsvp-te-2-PE-1-3-4" | RSVP-TE | 2 | 12 | 3 | "path-2-PE-1-3-4" |
"lsp-rsvp-te-3-PE-1-2-4" | RSVP-TE | 3 | 14 | 2 | "path-3-PE-1-2-4" |
"lsp-rsvp-te-4-PE-1-3-4" | RSVP-TE | 4 | 12 | 1 | "path-4-PE-1-3-4" |
- "lsp-rsvp-te-1-PE-1-2-4" carries 4/(4+3+1)=4/8=50% of the data traffic via "path-1-PE-1-2-4"
- "lsp-rsvp-te-2-PE-1-3-4" carries 3/8=37.5% of the data traffic via "path-2-PE-1-3-4"
- "lsp-rsvp-te-4-PE-1-3-4" carries 1/8=12.5% of the data traffic via "path-4-PE-1-3-4"
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 824 1 0 0.00
O 1169416 1002 0 0.00
1/1/c2/1 I 992 1 0 0.00
O 874168 748 0 0.00
1/1/c3/1 I 504 0 0 0.00
O 504 0 0 0.00
1/1/c4/1 I 504 0 0 0.00
O 294840 252 0 0.00
---snip---
1/1/c9/1 I 2048000 2000 0 0.00
O 0 0 0 0.00
=====================================================================
*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 rsvp:1 524276 Up bum 0
---snip---
Also RSVP-TE tunnel type no longer supported
# on PE-1:
configure service vpls 14 bgp-evpn mpls bgp 1 auto-bind-tunnel resolution-filter
no sr-te
no rsvp-te
- ldp:65539 carries all data traffic via port 1/1/c1/1
PE-1 receives 2000 packets per second on port 1/1/c9/1 and sends out 2001 packets per second on 1/1/c1/1 (~100%; ldp:65539).
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 504 0 0 0.00
O 2336824 2001 0 0.00
---snip---
1/1/c9/1 I 2048000 2000 0 0.00
O 0 0 0 0.00
=====================================================================
The
following show command confirms that the selected tunnel
is indeed the LDP
tunnel.*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 ldp:65539 524276 Up bum 0
---snip---
Also LDP tunnel type no longer supported
# on PE-1:
configure service vpls 14 bgp-evpn mpls bgp 1 auto-bind-tunnel resolution-filter
no sr-te
no rsvp-te
no ldp
- isis:524299 carries all data traffic via port 1/1/c1/1
PE-1 receives 2000 packets per second on port 1/1/c9/1 and sends out 2002 packets per second on 1/1/c1/1 (~100%; isis:524299).
*A:PE-1# monitor port all-ethernet-rates interval 3 repeat 5
=====================================================================
Monitor statistics for all Ethernet Port Rates
=====================================================================
Port-Id D Bits Packets Errors Util
---------------------------------------------------------------------
---snip---
-------------------------------------------------------------------------------
At time t = 15 sec (Mode: Rate)
-------------------------------------------------------------------------------
1/1/c1/1 I 1120 2 0 0.00
O 2337632 2002 0 0.00
---snip---
1/1/c9/1 I 2048000 2000 0 0.00
O 0 0 0 0.00
=====================================================================
The
following show command confirms that the selected tunnel
is indeed the SR-ISIS tunnel.*A:PE-1# show service id 14 evpn-mpls
===============================================================================
BGP EVPN-MPLS Dest (Instance 1)
===============================================================================
TEP Address Transport:Tnl Egr Label Oper Mcast Num
State MACs
-------------------------------------------------------------------------------
192.0.2.4 isis:524299 524276 Up bum 0
---snip---
Conclusion
SR OS supports weighted ECMP with per-LSP load balancing across multiple auto-bind SR-TE tunnels in EVPN Layer 2 services. The selection of a single tunnel type and the load balancing are configurable.