L2 Services with Auto-GRE Spoke-SDPs
This chapter provides information about L2 Services with Auto-GRE Spoke-SDPs.
Topics in this chapter include:
Applicability
This chapter was initially written for SR OS Release 16.0.R4, but the CLI in the current edition is based on SR OS Release 21.5.R1. Auto-GRE spoke-SDPs are supported in BGP-VPLS, BGP-AD, BGP-VPWS, and with FEC 129 spoke-SDPs in SR OS Release 16.0.R1, and later.
Overview
When the connectivity between nodes is IP-based (not MPLS), VPWS and VPLS services can use manually provisioned or auto-generated GRE transport tunnels. For auto-GRE transport tunnels, the signaling can be BGP or Targeted LDP (T-LDP). BGP signaling is more scalable than T-LDP, because T-LDP requires point-to-point sessions between communicating peers.
Auto-GRE spoke-SDPs can be used in the following services:
BGP-VPLS with BGP signaling
LDP VPLS using BGP-AD with T-LDP signaling
BGP-VPWS with BGP signaling
Dynamic Multi-segment Pseudowire (MS-PW) spoke-SDP Forwarding Equivalence Class (FEC) 129 with T-LDP signaling
PW templates for auto-GRE spoke-SDPs are configured with the creation-time parameter auto-gre-sdp. The auto-gre-sdp parameter can be combined with the creation-time parameter prefer-provisioned-sdp, but not with use-provisioned-sdp (because that might contradict the use of auto-GRE spoke-SDPs), as follows:
*A:PE-1>config>service# pw-template 3 name "PW3" ?
- pw-template <policy-id> [create] [prefer-provisioned-sdp] [name <name>]
[auto-gre-sdp]
- no pw-template <policy-id>
- pw-template <policy-id> use-provisioned-sdp [create] [name <name>]
---snip---
The auto-GRE SDP and SDP binding are created after a matching BGP route has been received. Subsequent requests for an auto-GRE SDP of the same type and to the same destination as an existing auto-GRE SDP will use the existing auto-GRE SDP.
Downstream fragmentation is allowed for auto-GRE SDPs by clearing the Don't Fragment (DF) bit in the GRE IP header. The following command controls fragmentation for a PW template:
configure
service
pw-template 40 name "PW40" auto-gre-sdp create
allow-fragmentation
exit
The following PW template parameters are not supported with GRE tunnels and will be ignored when a GRE SDP is auto-created:
Hash label
Entropy label
SDP include/exclude (there is no mechanism to configure an SDP admin group for auto-GRE SDPs)
However, these parameters are relevant for provisioned MPLS SDPs when the PW template is configured with prefer-provisioned-sdp.
The pw-template-binding parameter in the bgp context of the L2 service allows to configure the PW template to be used. It is possible to define multiple PW template bindings within a service. The mechanism for selecting the PW template is as follows:
In BGP-VPWS, BGP-VPLS, and BGP-AD services, the PW template binding selection is based on matching the configured import Route Targets (RTs) for a PW template binding with the RTs in the received routes.
The binding with the first matching RT is chosen. If no import RTs are configured, the lowest PW template binding ID is used.
It is not possible to add RTs to BGP-VPWS BGP updates using import or export policies, because they are ignored. However, the RT exported to select the destination service can be used on the receiving PE with PW template binding statement to influence the PW template to be selected; see the first use case in the Configuration section.
If the selected PW template is configured with prefer-provisioned-sdp and an SDP with a matching far-end address exists, the system chooses the SDP with the lowest metric from the tunnel table. If multiple matching SDPs with the same metric occur, the highest SDP ID that is operationally up is chosen.
The following tools command allows for PW template bindings to change:
*A:PE-1# tools perform service id 1 eval-pw-template ?
- eval-pw-template <policy-id> [allow-service-impact]
<policy-id> : [1..2147483647]
<allow-service-imp*> : keyword
The policy ID refers to the PW template currently in use. With the allow-service-impact option, the current binding will be torn down and re-signaled.
Configuration
Example topology shows the example topology with three PEs in AS 64500. Services will be configured on PE-1 and PE-2, and PE-3 is the route reflector (RR).
The initial configuration on the three PEs includes:
Cards, MDAs, ports
Router interfaces
IS-IS as IGP (alternatively, OSPF can be used)
Auto-GRE spoke-SDPs are configured in the following use cases:
BGP-VPLS with BGP signaling
BGP-AD in VPLS with T-LDP signaling
BGP-VPWS with BGP signaling
Dynamic MS-PW spoke-SDP FEC 129 with T-LDP signaling
In the first three use cases (BGP-VPLS, BGP-AD, BGP-VPWS), BGP is configured for the L2-VPN address family; in the last use case (dynamic MS-PW), BGP is configured for the MS-PW address family.
In each of the use cases, two L2 services will be configured using different PW templates with auto-gre-sdp: one with prefer-provisioned-sdp and one without.
Auto-GRE spoke-SDPs in BGP-VPLS
BGP-VPLS with auto-GRE spoke-SDPs shows the example topology with BGP-VPLSs 1 and 2 configured on PE-1 and PE-2. BGP is configured for the L2-VPN address family with PE-3 as Route Reflector (RR). The CEs are emulated through VPRNs configured on the PEs and connected to the VPLSs via Port Cross-connect (PXC).
BGP configuration
For the BGP-VPLS, BGP-AD, and BGP-VPWS use cases, BGP is configured with the L2-VPN address family. The BGP configuration on PE-1 and PE-2 is identical, as follows:
# on PE-1, PE-2::
configure
router Base
autonomous-system 64500
bgp
rapid-withdrawal
split-horizon
group "WAN"
family l2-vpn
type internal
neighbor 192.0.2.3
exit
exit
On RR PE-3, BGP is configured as follows:
configure
router Base
autonomous-system 64500
bgp
rapid-withdrawal
split-horizon
group "WAN"
family l2-vpn
cluster 192.0.2.3
type internal
neighbor 192.0.2.1
exit
neighbor 192.0.2.2
exit
exit
Service configuration
The configuration of BGP-VPLS services is described in the BGP VPLS chapter.
PW template 10 is configured with auto-gre-sdp; PW template 20 is configured with prefer-provisioned-sdp and auto-gre-sdp. Because only IP connectivity is present between the nodes (no MPLS), the provisioned SDP is GRE-based using BGP signaling (no T-LDP). VPLS 1 has PW template bindings with IDs 10 and 20; VPLS 2 is configured with PW template binding 20. The service configuration on PE-1 is as follows:
# on PE-1:
configure
service
sdp 12 create
signaling bgp
far-end 192.0.2.2
keep-alive
shutdown
exit
no shutdown
exit
pw-template 10 name "PW10-auto-GRE" auto-gre-sdp create
exit
pw-template 20 name "PW20-auto-GRE_prefer-prov" prefer-provisioned-sdp
auto-gre-sdp create
exit
vpls 1 name "BGP-VPLS-1" customer 1 create
description "BGP-VPLS with auto-GRE spoke-SDP"
bgp
route-distinguisher 64500:1
route-target export target:64500:1 import target:64500:1
pw-template-binding 10
exit
pw-template-binding 20
exit
exit
bgp-vpls
max-ve-id 100
ve-name "PE-1"
ve-id 1
exit
no shutdown
exit
stp
shutdown
exit
sap pxc-10.a:1 create # SAP to connect to CE-11
no shutdown
exit
no shutdown
exit
vpls 2 name "BGP-VPLS-2" customer 1 create
description "BGP-VPLS with auto-GRE spoke-SDP_prefer provisioned SDP"
bgp
route-distinguisher 64500:2
route-target export target:64500:2 import target:64500:2
pw-template-binding 20
exit
exit
bgp-vpls
max-ve-id 100
ve-name "PE-1"
ve-id 1
exit
no shutdown
exit
stp
shutdown
exit
sap pxc-10.a:2 create # SAP to connect to CE-12
no shutdown
exit
no shutdown
exit
The service configuration on PE-2 is similar, but the VE name is "PE-2" and the VE ID equals 2 instead, as follows:
# on PE-2:
configure
service
sdp 21 create
signaling bgp
far-end 192.0.2.1
keep-alive
shutdown
exit
no shutdown
exit
pw-template 10 name "PW10-auto-GRE" auto-gre-sdp create
exit
pw-template 20 name "PW20-auto-GRE_prefer-prov" prefer-provisioned-sdp
auto-gre-sdp create
exit
vpls 1 name "BGP-VPLS-1" customer 1 create
description "BGP-VPLS with auto-GRE spoke-SDP"
bgp
route-distinguisher 64500:1
route-target export target:64500:1 import target:64500:1
pw-template-binding 10
exit
pw-template-binding 20
exit
exit
bgp-vpls
max-ve-id 100
ve-name "PE-2"
ve-id 2
exit
no shutdown
exit
stp
shutdown
exit
sap pxc-10.a:1 create # SAP to connect to CE-21
no shutdown
exit
no shutdown
exit
vpls 2 name "BGP-VPLS-2" customer 1 create
description "BGP-VPLS with auto-GRE spoke-SDP_prefer provisioned SDP"
bgp
route-distinguisher 64500:2
route-target export target:64500:2 import target:64500:2
pw-template-binding 20
exit
exit
bgp-vpls
max-ve-id 100
ve-name "PE-2"
ve-id 2
exit
no shutdown
exit
stp
shutdown
exit
sap pxc-10.a:2 create # SAP to connect to CE-22
no shutdown
exit
no shutdown
exit
The following L2-VPN routes are received on PE-1: one for VPLS 1 with RD 64500:1 and another for VPLS 2 with RD 64500:2.
*A:PE-1# show router bgp routes l2-vpn
===============================================================================
BGP Router ID:192.0.2.1 AS:64500 Local AS:64500
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
l - leaked, x - stale, > - best, b - backup, p - purge
Origin codes : i - IGP, e - EGP, ? - incomplete
===============================================================================
BGP L2VPN Routes
===============================================================================
Flag RouteType Prefix MED
RD SiteId Label
Nexthop VeId BlockSize LocalPref
As-Path BaseOffset vplsLabelBa
se
-------------------------------------------------------------------------------
u*>i VPLS - - 0
64500:1 - -
192.0.2.2 2 8 100
No As-Path 1 524280
u*>i VPLS - - 0
64500:2 - -
192.0.2.2 2 8 100
No As-Path 1 524272
-------------------------------------------------------------------------------
Routes : 2
===============================================================================
VPLS 1 is configured with two PW template bindings without import RT. Because the PW template binding with the lowest ID is preferred, PW template 10 is used and therefore, the following GRE SDP 32767 is auto-created:
*A:PE-1# show service id 1 sdp detail
===============================================================================
Services: Service Destination Points Details
===============================================================================
-------------------------------------------------------------------------------
Sdp Id 32767:4294967295 -(192.0.2.2)
-------------------------------------------------------------------------------
Description : (Not Specified)
SDP Id : 32767:4294967295 Type : BgpVpls
PW-Template Id : 10
Split Horiz Grp : (Not Specified)
Etree Root Leaf Tag: Disabled Etree Leaf AC : Disabled
VC Type : Ether VC Tag : n/a
Admin Path MTU : 0 Oper Path MTU : 8954
Delivery : GRE
Far End : 192.0.2.2 Tunnel Far End : n/a
Oper Tunnel Far End: 192.0.2.2
---snip---
Admin State : Up Oper State : Up
MinReqd SdpOperMTU : 1514
Acct. Pol : None Collect Stats : Disabled
Ingress Label : 524281 Egress Label : 524280
---snip---
Last Status Change : 06/23/2021 14:24:54 Signaling : BGP
---snip---
VPLS 2 is configured with PW template binding 20, which prefers provisioned SDPs, so the provisioned SDP 12 is used, as follows:
*A:PE-1# show service id 2 sdp
===============================================================================
Services: Service Destination Points
===============================================================================
SdpId Type Far End addr Adm Opr I.Lbl E.Lbl
-------------------------------------------------------------------------------
12:4294967294 BgpVpls 192.0.2.2 Up Up 524273 524272
-------------------------------------------------------------------------------
Number of SDPs : 1
-------------------------------------------------------------------------------
===============================================================================
In VPLS 1, the PW template binding selection can be changed by configuring a non-matching import RT to PW template 10, as follows:
# on PE-1:
configure
service
vpls "BGP-VPLS-1"
bgp
pw-template-binding 10 import-rt "target:64500:999"
exit
exit
This does not change the selected PW template during service operation and PW template 10 remains in use, as follows:
*A:PE-1# show service id 1 sdp detail | match "PW-Template"
PW-Template Id : 10
The following tools command forces the system to re-evaluate the PW template binding:
*A:PE-1# tools perform service id 1 eval-pw-template 10 allow-service-impact
eval-pw-template succeeded for Svc 1 32767:4294967295 Policy 10
When the PW template binding is re-evaluated, PW template binding 20 is selected and the provisioned SDP 12 is used, as follows:
*A:PE-1# show service id 1 sdp detail | match "PW-Template"
PW-Template Id : 20
*A:PE-1# show service id 1 sdp
===============================================================================
Services: Service Destination Points
===============================================================================
SdpId Type Far End addr Adm Opr I.Lbl E.Lbl
-------------------------------------------------------------------------------
12:4294967293 BgpVpls 192.0.2.2 Up Up 524281 524280
-------------------------------------------------------------------------------
Number of SDPs : 1
-------------------------------------------------------------------------------
===============================================================================
Auto-GRE spoke-SDPs in LDP-VPLS using BGP-AD
LDP-VPLS using BGP-AD with auto-GRE Spoke-SDPs shows the example topology with VPLSs 3 and 4 configured with BGP-AD on PE-1 and PE-2. The BGP configuration is identical to the one for BGP-VPLS.
The following T-LDP session is configured between PE-1 and PE-2:
# on PE-1:
configure
router Base
ldp
targeted-session
peer 192.0.2.2
no shutdown
exit
exit
# on PE-2:
configure
router Base
ldp
targeted-session
peer 192.0.2.1
no shutdown
exit
exit
The following T-LDP signaled SDP is configured on PE-1 and PE-2:
# on PE-1:
configure
service
sdp 120 create
far-end 192.0.2.2
keep-alive
shutdown
exit
no shutdown
exit
# on PE-2:
configure
service
sdp 120 create
far-end 192.0.2.1
keep-alive
shutdown
exit
no shutdown
exit
The service configuration on PE-1 and PE-2 is as follows; see chapter LDP VPLS Using BGP Auto-Discovery for a description of BGP-AD in LDP VPLS. PW templates 10 and 20 are the same as in the preceding example.
# on PE-1, PE-2:
configure
service
pw-template 10 name "PW10-auto-GRE" auto-gre-sdp create
exit
pw-template 20 name "PW20-auto-GRE_prefer-prov" prefer-provisioned-sdp
auto-gre-sdp create
exit
vpls 3 name "BGP-AD VPLS-3" customer 1 create
description "BGP-AD for LDP VPLS with auto-GRE spoke-SDP"
bgp
route-distinguisher 64500:3
route-target export target:64500:3 import target:64500:3
pw-template-binding 10
exit
pw-template-binding 20
exit
exit
bgp-ad
vpls-id 64500:3
no shutdown
exit
stp
shutdown
exit
sap pxc-10.a:3 create # SAP to connect to CE-13 (PE-1) or CE-23 (PE-2)
no shutdown
exit
no shutdown
exit
vpls 4 name "BGP-AD VPLS-4" customer 1 create
description "BGP-AD for LDP VPLS with auto-GRE spoke-SDP pref-prov-SDP"
bgp
route-distinguisher 64500:4
route-target export target:64500:4 import target:64500:4
pw-template-binding 20
exit
exit
bgp-ad
vpls-id 64500:4
no shutdown
exit
stp
shutdown
exit
sap pxc-10.a:4 create # SAP to connect to CE-14 (PE-1) or CE-24 (PE-2)
no shutdown
exit
no shutdown
exit
PE-1 has received the following L2-VPN BGP-AD routes:
*A:PE-1# show router bgp routes l2-vpn bgp-ad
===============================================================================
BGP Router ID:192.0.2.1 AS:64500 Local AS:64500
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
l - leaked, x - stale, > - best, b - backup, p - purge
Origin codes : i - IGP, e - EGP, ? - incomplete
===============================================================================
BGP L2VPN-AD Routes
===============================================================================
Flag RouteType Prefix MED
RD SiteId Label
Nexthop VeId BlockSize LocalPref
As-Path BaseOffset vplsLabelBa
se
-------------------------------------------------------------------------------
u*>i AutoDiscovery 192.0.2.2 - 0
64500:3 - -
192.0.2.2 - - 100
No As-Path - -
u*>i AutoDiscovery 192.0.2.2 - 0
64500:4 - -
192.0.2.2 - - 100
No As-Path - -
-------------------------------------------------------------------------------
Routes : 2
===============================================================================
The following shows the used SDPs on PE-1: BGP-signaled SDP 12 (used by VPLS 1 and 2) and T-LDP-signaled SDPs 120 and 32767.
*A:PE-1# show service sdp
============================================================================
Services: Service Destination Points
============================================================================
SdpId AdmMTU OprMTU Far End Adm Opr Del LSP Sig
----------------------------------------------------------------------------
12 0 8954 192.0.2.2 Up Up GRE n/a BGP
120 0 8954 192.0.2.2 Up Up GRE n/a TLDP
32767 0 8954 192.0.2.2 Up Up GRE n/a TLDP
----------------------------------------------------------------------------
Number of SDPs : 3
----------------------------------------------------------------------------
Legend: R = RSVP, L = LDP, B = BGP, M = MPLS-TP, n/a = Not Applicable
I = SR-ISIS, O = SR-OSPF, T = SR-TE, F = FPE
============================================================================
The following shows that PW template 10 is used in VPLS 3 and that auto-GRE SDP 32767 is used, with T-LDP signaling:
*A:PE-1# show service id 3 sdp detail
===============================================================================
Services: Service Destination Points Details
===============================================================================
-------------------------------------------------------------------------------
Sdp Id 32767:4294967292 -(192.0.2.2)
-------------------------------------------------------------------------------
Description : (Not Specified)
SDP Id : 32767:4294967292 Type : BgpAd
PW-Template Id : 10
AGI : 64500:3 SDP Bind Source : bgp-l2vpn
Local AII : 192.0.2.1
Remote AII : 192.0.2.2
Split Horiz Grp : (Not Specified)
Etree Root Leaf Tag: Disabled Etree Leaf AC : Disabled
VC Type : Ether VC Tag : n/a
Admin Path MTU : 0 Oper Path MTU : 8954
Delivery : GRE
Far End : 192.0.2.2 Tunnel Far End : n/a
Oper Tunnel Far End: 192.0.2.2
---snip---
Admin State : Up Oper State : Up
---snip---
Last Status Change : 06/23/2021 14:30:31 Signaling : TLDP
---snip---
The following shows that the T-LDP signaled GRE SDP 120 is used in VPLS 4, not the BGP-signaled GRE SDP 12:
*A:PE-1# show service id 4 sdp
===============================================================================
Services: Service Destination Points
===============================================================================
SdpId Type Far End addr Adm Opr I.Lbl E.Lbl
-------------------------------------------------------------------------------
120:4294967291 BgpAd 192.0.2.2 Up Up 524269 524269
-------------------------------------------------------------------------------
Number of SDPs : 1
-------------------------------------------------------------------------------
===============================================================================
Auto-GRE spoke-SDPs in BGP-VPWS
BGP-VPWS with auto-GRE spoke-SDPs shows the example topology with BGP-VPWS Epipes 5 and 6 on PE-1 and PE-2. The BGP configuration is identical to the one for BGP-VPLS.
Chapter BGP Virtual Private Wire Services describes the configuration of BGP VPWS. The configuration of Epipes 5 and 6 on PE-1 is as follows:
# on PE-1:
configure
service
pw-template 10 name "PW10-auto-GRE" auto-gre-sdp create
exit
pw-template 20 name "PW20-auto-GRE_prefer-prov" prefer-provisioned-sdp
auto-gre-sdp create
exit
epipe 5 name "BGP-VPWS-5" customer 1 create
description "BGP-VPWS with auto-GRE spoke-SDP"
bgp
route-distinguisher 64500:5
route-target export target:64500:5 import target:64500:5
pw-template-binding 10
exit
pw-template-binding 20
exit
exit
bgp-vpws
ve-name "PE-1"
ve-id 1
exit
remote-ve-name "PE-2"
ve-id 2
exit
no shutdown
exit
sap pxc-10.a:5 create # SAP to connect to CE-15
no shutdown
exit
no shutdown
exit
epipe 6 name "BGP-VPWS-6" customer 1 create
description "BGP-VPWS with auto-GRE spoke-SDP_prefer provisioned SDP"
bgp
route-distinguisher 64500:6
route-target export target:64500:6 import target:64500:6
pw-template-binding 20
exit
exit
bgp-vpws
ve-name "PE-1"
ve-id 1
exit
remote-ve-name "PE-2"
ve-id 2
exit
no shutdown
exit
sap pxc-10.a:6 create # SAP to connect to CE-16
no shutdown
exit
no shutdown
exit
The configuration of the Epipes is similar on PE-2, but the VE names and VE IDs are different, as follows:
# on PE-2:
configure
service
epipe 5 name "BGP-VPWS-5" customer 1 create
description "BGP-VPWS with auto-GRE spoke-SDP"
bgp
route-distinguisher 64500:5
route-target export target:64500:5 import target:64500:5
pw-template-binding 10
exit
pw-template-binding 20
exit
exit
bgp-vpws
ve-name "PE-2"
ve-id 2
exit
remote-ve-name "PE-1"
ve-id 1
exit
no shutdown
exit
sap pxc-10.a:5 create # SAP to connect to CE-25
no shutdown
exit
no shutdown
exit
epipe 6 name "BGP-VPWS-6" customer 1 create
description "BGP-VPWS with auto-GRE spoke-SDP_prefer provisioned SDP"
bgp
route-distinguisher 64500:6
route-target export target:64500:6 import target:64500:6
pw-template-binding 20
exit
exit
bgp-vpws
ve-name "PE-2"
ve-id 2
exit
remote-ve-name "PE-1"
ve-id 1
exit
no shutdown
exit
sap pxc-10.a:6 create # SAP to connect to CE-26
no shutdown
exit
no shutdown
exit
PE-1 receives the following BGP-VPWS routes from PE-2:
*A:PE-1# show router bgp routes l2-vpn bgp-vpws
===============================================================================
BGP Router ID:192.0.2.1 AS:64500 Local AS:64500
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
l - leaked, x - stale, > - best, b - backup, p - purge
Origin codes : i - IGP, e - EGP, ? - incomplete
===============================================================================
BGP L2VPN-VPWS Routes
===============================================================================
Flag RouteType Prefix MED
RD SiteId Label
Nexthop VeId BlockSize LocalPref
As-Path BaseOffset vplsLabelBa
se
-------------------------------------------------------------------------------
u*>i VPWS - - 0
64500:5 - -
192.0.2.2 2 1 100
No As-Path 1 524268
u*>i VPWS - - 0
64500:6 - -
192.0.2.2 2 1 100
No As-Path 1 524267
-------------------------------------------------------------------------------
Routes : 2
===============================================================================
The following SDP bindings are used on PE-1: the first two are used by BGP-VPLS services VPLS 1 and 2, the third and fourth are used by BGP-AD in LDP VPLS 3 and 4, and the last two are used by BGP-VPWS services Epipe 5 and 6. For the last two, SDP 32766 is auto-created, whereas SDP 12 is provisioned with BGP signaling.
*A:PE-1# show service sdp-using
===============================================================================
SDP Using
===============================================================================
SvcId SdpId Type Far End Opr I.Label E.Label
State
-------------------------------------------------------------------------------
1 12:4294967293 BgpVp* 192.0.2.2 Up 524281 524280
2 12:4294967294 BgpVp* 192.0.2.2 Up 524273 524272
3 32767:4294967292 BgpAd 192.0.2.2 Up 524270 524270
4 120:4294967291 BgpAd 192.0.2.2 Up 524269 524269
5 32766:4294967290 BgpVp* 192.0.2.2 Up 524268 524268
6 12:4294967289 BgpVp* 192.0.2.2 Up 524267 524267
-------------------------------------------------------------------------------
Number of SDPs : 6
-------------------------------------------------------------------------------
===============================================================================
* indicates that the corresponding row element may have been truncated.
Epipe 5 uses the following auto-GRE SDP 32766 with BGP signaling:
*A:PE-1# show service id 5 sdp detail
===============================================================================
Services: Service Destination Points Details
===============================================================================
-------------------------------------------------------------------------------
Sdp Id 32766:4294967290 -(192.0.2.2)
-------------------------------------------------------------------------------
Description : (Not Specified)
SDP Id : 32766:4294967290 Type : BgpVpws
PW-Template Id : 10
VC Type : Ether VC Tag : n/a
Admin Path MTU : 0 Oper Path MTU : 8954
Delivery : GRE
Far End : 192.0.2.2 Tunnel Far End : n/a
Oper Tunnel Far End: 192.0.2.2
---snip---
Admin State : Up Oper State : Up
---snip---
Last Status Change : 06/23/2021 14:36:00 Signaling : BGP
---snip---
PW template 20 is used in Epipe 6, so the BGP-signaled GRE SDP 12 is used, as follows:
*A:PE-1# show service id 6 sdp
===============================================================================
Services: Service Destination Points
===============================================================================
SdpId Type Far End addr Adm Opr I.Lbl E.Lbl
-------------------------------------------------------------------------------
12:4294967289 BgpVpws 192.0.2.2 Up Up 524267 524267
-------------------------------------------------------------------------------
Number of SDPs : 1
-------------------------------------------------------------------------------
===============================================================================
Auto-GRE spoke-SDPs in dynamic MS-PW spoke-SDP FEC
Chapter Multi-Segment Pseudowire Routing describes the configuration for dynamic MS-PW spoke-SDP FEC.
Dynamic MS-PW spoke-SDP FEC with auto-GRE spoke-SDPs shows the example topology with PE-1 and PE-2 as Terminating PEs (T-PEs) and PE-3 as Switching PE (S-PE). Port 1/1/1 on PE-1 (toward PE-2) and port 1/1/2 on PE-2 (toward PE-1) are disabled, as follows:
# on PE-1:
configure
port 1/1/1
shutdown
# on PE-2:
configure
port 1/1/2
shutdown
BGP-VPWS Epipes 7 and 8 are configured on PE-1 and PE-2.
T-LDP is configured between PE-1 and PE-3 and between PE-2 and PE-3, as follows:
# on PE-1, PE-2:
configure
router Base
ldp
targeted-session
peer 192.0.2.3
no shutdown
# on PE-3:
configure
router Base
ldp
targeted-session
peer 192.0.2.1
no shutdown
exit
peer 192.0.2.2
no shutdown
exit
BGP configuration
BGP is configured for the MS-PW address family. On the T-PEs, an export policy is required to export MS-PW routes; in this case, a default policy matching all the MS-PW routes is configured. The configuration on PE-1 and PE-2 is as follows:
# on PE-1, PE-2:
configure
router Base
policy-options
begin
policy-statement "export ms-pw"
entry 10
from
family ms-pw
exit
action accept
origin igp
exit
exit
exit
commit
exit
bgp
rapid-withdrawal
group "WAN"
family ms-pw
type internal
neighbor 192.0.2.3
export "export ms-pw"
exit
exit
exit
S-PE (and RR) PE-3 is configured for the MS-PW address family and has next-hop-self enabled, as follows:
# on PE-3:
configure
router Base
bgp
rapid-withdrawal
split-horizon
group "WAN"
family ms-pw
next-hop-self
type internal
cluster 192.0.2.3
neighbor 192.0.2.1
exit
neighbor 192.0.2.2
exit
exit
exit
Service configuration
Each T-PE and S-PE is configured with an SPE address. On S-PE PE-3, the SPE address is configured as follows:
# on PE-3:
configure
service
pw-routing
spe-address 64500:192.0.2.3
exit
The service configuration on PE-1 is as follows:
# on PE-1:
configure
service
pw-routing
spe-address 64500:192.0.2.1
local-prefix 64500:192.0.2.1 create
advertise-bgp route-distinguisher 64500:7
advertise-bgp route-distinguisher 64500:8
exit
exit
pw-template 10 name "PW10-auto-GRE" auto-gre-sdp create
exit
pw-template 20 name "PW20-auto-GRE_prefer-prov" prefer-provisioned-sdp
auto-gre-sdp create
exit
epipe 7 name "Epipe-7 MS-PW" customer 1 create
description "Epipe with dynamic MS-PW spoke-SDP FEC"
sap pxc-10.a:7 create # SAP to connect to CE-17
no shutdown
exit
spoke-sdp-fec 7 fec 129 aii-type 2 create
pw-template-bind 10
saii-type2 64500:192.0.2.1:7
taii-type2 64500:192.0.2.2:7
no shutdown
exit
no shutdown
exit
epipe 8 name "Epipe-8 MS-PW" customer 1 create
description "Epipe with dynamic MS-PW spoke-SDP FEC_pref-prov"
sap pxc-10.a:8 create # SAP to connect to CE-18
no shutdown
exit
spoke-sdp-fec 8 fec 129 aii-type 2 create
pw-template-bind 20
saii-type2 64500:192.0.2.1:8
taii-type2 64500:192.0.2.2:8
no shutdown
exit
no shutdown
exit
On PE-2, the following service configuration is similar, with different SPE address, local prefix, Source Attachment Individual Identifier (SAII), and Target Attachment Individual Identifier (TAII). The SAIIs for the Epipes on PE-2 match the TAIIs for the matching Epipes on PE-1 and the TAIIs on PE-2 match the SAIIs on PE-1.
# on PE-2:
configure
service
pw-routing
spe-address 64500:192.0.2.2
local-prefix 64500:192.0.2.2 create
advertise-bgp route-distinguisher 64500:7
advertise-bgp route-distinguisher 64500:8
exit
exit
epipe 7 name "Epipe-7 MS-PW" customer 1 create
description "Epipe with dynamic MS-PW spoke-SDP FEC"
sap pxc-10.a:7 create # SAP to connect to CE-27
no shutdown
exit
spoke-sdp-fec 7 fec 129 aii-type 2 create
pw-template-bind 10
saii-type2 64500:192.0.2.2:7
taii-type2 64500:192.0.2.1:7
no shutdown
exit
no shutdown
exit
epipe 8 name "Epipe-8 MS-PW" customer 1 create
description "Epipe with dynamic MS-PW spoke-SDP FEC_pref-prov"
sap pxc-10.a:8 create # SAP to connect to CE-28
no shutdown
exit
spoke-sdp-fec 8 fec 129 aii-type 2 create
pw-template-bind 20
saii-type2 64500:192.0.2.2:8
taii-type2 64500:192.0.2.1:8
no shutdown
exit
no shutdown
exit
The following BGP MS-PW routes are used on PE-1:
*A:PE-1# show router bgp routes ms-pw
===============================================================================
BGP Router ID:192.0.2.1 AS:64500 Local AS:64500
===============================================================================
Legend -
Status codes : u - used, s - suppressed, h - history, d - decayed, * - valid
l - leaked, x - stale, > - best, b - backup, p - purge
Origin codes : i - IGP, e - EGP, ? - incomplete
===============================================================================
BGP MSPW Routes
===============================================================================
Flag Network RD
Nexthop AII-Type2/Preflen
As-Path
-------------------------------------------------------------------------------
u*>i 64500:192.0.2.2 64500:7
192.0.2.2 64500:192.0.2.2:0/64
No As-Path
u*>i 64500:192.0.2.2 64500:8
192.0.2.2 64500:192.0.2.2:0/64
No As-Path
-------------------------------------------------------------------------------
Routes : 2
===============================================================================
The following spoke-SDP FECs are used on PE-1. Auto-GRE SDP 32766 is used in Epipe 7 and provisioned LDP-signaled SDP 120 is used in Epipe 8.
*A:PE-1# show service spoke-sdp-fec-using
===============================================================================
Service Spoke-SDP-Fec Information
===============================================================================
SvcId SpokeSdpFec Oper-SdpBind SAII-Type2
Path Retries/Secs TAII-Type2
Left
-------------------------------------------------------------------------------
7 7 32766:4294967288 64500:192.0.2.1:7
n/a 0/0 64500:192.0.2.2:7
8 8 120:4294967287 64500:192.0.2.1:8
n/a 0/0 64500:192.0.2.2:8
-------------------------------------------------------------------------------
Entries found: 2
===============================================================================
Auto-GRE SDP 32766 with T-LDP signaling is used in Epipe 7 on PE-1, as follows:
*A:PE-1# show service id 7 sdp detail
===============================================================================
Services: Service Destination Points Details
===============================================================================
-------------------------------------------------------------------------------
Sdp Id 32766:4294967288 -(192.0.2.2)
-------------------------------------------------------------------------------
Description : (Not Specified)
SDP Id : 32766:4294967288 Type : MS-PW
PW-Template Id : 10
SAII Type2 : 64500:192.0.2.1:7
TAII Type2 : 64500:192.0.2.2:7
VC Type : Ether VC Tag : n/a
Admin Path MTU : 0 Oper Path MTU : 8954
Delivery : GRE
Far End : 192.0.2.2 Tunnel Far End : n/a
Oper Tunnel Far End: 192.0.2.2
---snip---
Admin State : Up Oper State : Up
MinReqd SdpOperMTU : 1514
Adv Service MTU : n/a
Acct. Pol : None Collect Stats : Disabled
Ingress Label : 524270 Egress Label : 524270
---snip---
Last Status Change : 06/23/2021 14:42:31 Signaling : TLDP
---snip---
The following provisioned GRE SDP with T-LDP signaling is used in Epipe 8 on PE-1:
*A:PE-1# show service id 8 sdp
===============================================================================
Services: Service Destination Points
===============================================================================
SdpId Type Far End addr Adm Opr I.Lbl E.Lbl
-------------------------------------------------------------------------------
120:4294967287 MS-PW 192.0.2.2 Up Up 524269 524269
-------------------------------------------------------------------------------
Number of SDPs : 1
-------------------------------------------------------------------------------
===============================================================================
Conclusion
In IP-based networks, auto-GRE spoke-SDPs can be used in VPWS and VPLS services. Manually configured GRE tunnels are not an option in networks—such as LTE networks—where it is common to assign IP addresses dynamically from a pool of addresses, but auto-GRE spoke-SDPs can be applied instead.