SRv6 VPLS services

VPLS services support SRv6 End.DT2M behavior for BUM traffic and End.DT2U behavior for known unicast traffic. The SRv6 SID for End.DT2M is signaled by EVPN Inclusive Multicast Ethernet Tag (IMET) routes, whereas the SID for End.DT2U is signaled along with EVPN MAC/IP routes.

Use the following contexts to configure a VPLS service for SRv6:

MD-CLI

configure service vpls "1" segment-routing <instance-id>
   
configure service vpls "1" bgp-evpn segment-routing-v6 <number>

classic CLI

configure service vpls "1" segment-routing-v6 <instance-id>

configure service vpls "1" bgp-evpn segment-routing-v6 srv6-instance 1 default-locator

The following conditions apply for a VPLS service for SRv6:

The SRv6 VPLS is configured with the locator that is used. This determines the SID structure and value that is advertised along with the EVPN Inclusive Multicast Ethernet Tag (IMET) and MAC/IP routes for the service.
A single SRv6 instance with a single locator is supported on VPLS services.
SRv6 VPLS services use End.DT2M and End.DT2U SIDs. Their corresponding function values, if not configured, are allocated automatically by the router. Dynamic or static, both function values (End.DT2M and End.DT2U) are needed so that the EVPN routes for the services are advertised. While both values are different locally on the service, the router accepts the same value for End.DT2M and End.DT2U functions from a remote PE for the same service.
The following are supported in SRv6 VPLS services:

force-vlan-vc-forwarding

used to preserve one VLAN tag in the payload of the SRv6 tunnel

default-route-tag

used to match BGP EVPN routes for the service on export policies, typically to add or modify BGP attributes

oper-group

required for fault-propagation purposes

protected-src-mac-violation-action discard

required for loop avoidance along with mac-duplication blackhole

split-horizon-group

used for seamless integration with spoke SDPs and migration from EVPN-MPLS services (in multi-instance services

route-next-hop

used to control the BGP next-hop used for service routes. If not configured, it is system-ipv4 by default

source-address

if not configured, it is inherited from the locator’s source address. The source address does not need to be reachable or even exist on a local interface. This is possible because the source address is not looked up in the datapath at the remote PE

resolution {route-table | tunnel-table | fallback-tunnel-to-route-table}

used to set the resolution of SRv6 routes in the route table or tunnel table (needed for SRv6 policy), and even a the fallback from tunnel to route-table resolution

Example: Configuration example and the allocated functions on the PE

A:PE-2# configure service vpls 1900 
A:PE-2>config>service>vpls# info 
            segment-routing-v6 1 create
                locator “LOC-1"
                    function
                        end-dt2u
                        end-dt2m
                    exit
                exit
            exit
            bgp
            exit
            bgp-evpn
                evi 1900
                segment-routing-v6 bgp 1 srv6-instance 1 default-locator "LOC-1" create
                    source-address 2001:db8::2
                    route-next-hop 2001:db8::2
                    no shutdown
                exit
            exit
            stp
                shutdown
            exit
            no shutdown

show service id 1900 segment-routing-v6 instance 1 

===============================================================================
Segment Routing v6 Instance 1 Service 1900
===============================================================================
Locator                                                           
  Type         Function  SID                                     Status
-------------------------------------------------------------------------------
LOC-1
  End.DT2U       *504273 cafe:1:0:2:7b1d:1000::                  ok
  End.DT2M       *504272 cafe:1:0:2:7b1d::                       ok
===============================================================================

A:PE-2# show router segment-routing-v6 local-sid end-dt2u end-dt2m              

===============================================================================
Segment Routing v6 Local SIDs
===============================================================================
SID                                               Type           Function
  Locator                                                        
  Context                                                        
-------------------------------------------------------------------------------
cafe:1:0:2:7b1d::                                 End.DT2M       504272
  LOC-1
  SvcId: 1900 Name: bd-1900-srv6
cafe:1:0:2:7b1d:1000::                            End.DT2U       504273
  LOC-1
  SvcId: 1900 Name: bd-1900-srv6
-------------------------------------------------------------------------------
SIDs : 2
-------------------------------------------------------------------------------
===============================================================================

Example: Remote PEs

If the remote PEs attached to the same VPLS services are configured in a similar way, the EVPN destinations for BUM and unicast traffic are created and can be displayed as follows:

show service id 1900 segment-routing-v6 destinations 

===============================================================================
TEP, SID
===============================================================================
Instance  TEP Address                Segment Id                 SupBcasDom Num
 Mcast                                                                     MACs
-------------------------------------------------------------------------------
1         2001:db8::3                cafe:1:0:3:7b1d:7000::      No        0
 BUM                                                                       
1         2001:db8::4                cafe:1:0:4:7:b1db::         No        0
 BUM                                                                       
1         2001:db8::5                cafe:1:0:5:7b1d:d000::      No        0
 BUM                                                                       
1         2001:db8::5                cafe:1:0:5:7b1d:e000::      No        1
 -                                                                         
-------------------------------------------------------------------------------
Number of TEP, SID: 4
-------------------------------------------------------------------------------
===============================================================================

===============================================================================
Segment Routing v6 Ethernet Segment Dest
===============================================================================
Instance  Eth SegId                       Num. Macs     Last Change
-------------------------------------------------------------------------------
No Matching Entries
===============================================================================

Example: IMET and MAC/IP routes for SRv6 transport, received on a router

EVPN IMET and MAC/IP routes for SRv6 are advertised and expected to be received with the SRv6 Services TLV, which includes all the information related to the SRv6 SID and behavior that is used by the receiving router. As for the other services, transposition procedures are followed as in Transposition procedures when advertising service routes.

show router bgp routes evpn incl-mcast community target:64500:1900 next-hop 2001:db8::5 hunt 
===============================================================================
 BGP Router ID:192.0.2.2        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 EVPN Inclusive-Mcast Routes
===============================================================================
-------------------------------------------------------------------------------
RIB In Entries
-------------------------------------------------------------------------------
Network        : n/a
Nexthop        : 2001:db8::5
Path Id        : None                   
From           : 2001:db8::5
Res. Nexthop   : fe80::b449:1ff:fe01:1f
Local Pref.    : 100                    Interface Name : int-PE-2-PE-5
Aggregator AS  : None                   Aggregator     : None
Atomic Aggr.   : Not Atomic             MED            : None
AIGP Metric    : None                   IGP Cost       : 10
Connector      : None
Community      : target:64500:1900
Cluster        : No Cluster Members
Originator Id  : None                   Peer Router Id : 192.0.2.5
Flags          : Used Valid Best IGP 
Route Source   : Internal
AS-Path        : No As-Path
EVPN type      : INCL-MCAST             
Tag            : 0                      
Originator IP  : 2001:db8::5
Route Dist.    : 192.0.2.5:1900
Route Tag      : 0                      
Neighbor-AS    : n/a
Orig Validation: N/A                    
Source Class   : 0                      Dest Class     : 0
Add Paths Send : Default                
Last Modified  : 00h14m18s              
SRv6 TLV Type  : SRv6 L2 Service TLV (6)
SRv6 SubTLV    : SRv6 SID Information (1)
Sid            : cafe:1:0:5::
Full Sid       : cafe:1:0:5:7b1d:d000::
Behavior       : End.DT2M (24)
SRv6 SubSubTLV : SRv6 SID Structure (1)
Loc-Block-Len  : 32                     Loc-Node-Len   : 32
Func-Len       : 20                     Arg-Len        : 0
Tpose-Len      : 20                     Tpose-offset   : 64
-------------------------------------------------------------------------------
PMSI Tunnel Attributes : 
Tunnel-type    : Ingress Replication    
Flags          : Type: RNVE(0) BM: 0 U: 0 Leaf: not required
MPLS Label     : 8068560                
Tunnel-Endpoint: 2001:db8::5
-------------------------------------------------------------------------------
 
-------------------------------------------------------------------------------
RIB Out Entries
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Routes : 1
===============================================================================

show router bgp routes evpn mac community target:64500:1900 next-hop 2001:db8::5 hunt        
===============================================================================
 BGP Router ID:192.0.2.2        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 EVPN MAC Routes
===============================================================================
-------------------------------------------------------------------------------
RIB In Entries
-------------------------------------------------------------------------------
Network        : n/a
Nexthop        : 2001:db8::5
Path Id        : None                   
From           : 2001:db8::5
Res. Nexthop   : fe80::b449:1ff:fe01:1f
Local Pref.    : 100                    Interface Name : int-PE-2-PE-5
Aggregator AS  : None                   Aggregator     : None
Atomic Aggr.   : Not Atomic             MED            : None
AIGP Metric    : None                   IGP Cost       : 10
Connector      : None
Community      : target:64500:1900
                 mac-mobility:Seq:0/Static
Cluster        : No Cluster Members
Originator Id  : None                   Peer Router Id : 192.0.2.5
Flags          : Used Valid Best IGP 
Route Source   : Internal
AS-Path        : No As-Path
EVPN type      : MAC                    
ESI            : ESI-0
Tag            : 0                      
IP Address     : n/a
Route Dist.    : 192.0.2.5:1900         
Mac Address    : 00:ca:ca:de:ba:ca      
MPLS Label1    : LABEL 504286           MPLS Label2    : n/a
Route Tag      : 0                      
Neighbor-AS    : n/a
Orig Validation: N/A                    
Source Class   : 0                      Dest Class     : 0
Add Paths Send : Default                
Last Modified  : 00h14m26s              
SRv6 TLV Type  : SRv6 L2 Service TLV (6)
SRv6 SubTLV    : SRv6 SID Information (1)
Sid            : cafe:1:0:5::
Full Sid       : cafe:1:0:5:7b1d:e000::
Behavior       : End.DT2U (23)
SRv6 SubSubTLV : SRv6 SID Structure (1)
Loc-Block-Len  : 32                     Loc-Node-Len   : 32
Func-Len       : 20                     Arg-Len        : 0
Tpose-Len      : 20                     Tpose-offset   : 64
 
-------------------------------------------------------------------------------
RIB Out Entries
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Routes : 1
===============================================================================