SRv6 inter-domain mapping SIDsJuniper NetworksEmbassy Business ParkBangaloreKA560093Indiasalih@juniper.netJuniper NetworksEmbassy Business ParkBangaloreKA560093Indiashraddha@juniper.netJuniper NetworksEmbassy Business ParkBangaloreKA560093Indiamrajesh@juniper.netJuniper NetworksHerndon20171VirginiaUSArbonica@juniper.net
Routing Area
SPRING Working GroupSegment RoutingIPv6This document describes three new SRv6 end point behaviors, named
END.REPLACE, END.REPLACEB6 and END.DB6. These SIDs are used in distributed inter-domain
solutions for connecting SRv6 domains. This behavior is normally executed on border routers
between different domains. These SIDs can also be used to provide multiple
intent based paths across these domains.Segment Routing (SR) allows source
nodes to steer packets through SR paths. It can be implemented over
IPv6 or MPLS
. When SR is implemented over IPv6, it is called SRv6.
This document describes three new SRv6 endpoint behaviors, named
END.REPLACE, END.REPLACEB6 and END.DB6. These SIDs help in building paths
over different SRv6 domans in a distributed manner.
These extensions will aid in end to end SRv6 intent based path stitching as well.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only
when, they appear in all capitals, as shown here.The document describes
different models of topology applicable for the use-cases mentioned in this document.
This requirement is mentioned in the document
under
the section 4.1.1.
The above diagram
has three different ASes (AS1, AS2 and AS3). All the three
domains are having SRv6. BGP is used for getting option C style
connectivity end to end from PE1 to PE2.
The above diagram
shows two different SRv6 domains, AS1 and AS2. Services are running between PE1 and PE2
in option B style.
The requirement here is to avoid service route lookup on ABR1 and ABR2 to provide option B style
end to end connectivity.
Here we will describe the new SRv6 SID behaviorsFor the use-case mentioned under END.REPLACE SID is applicableThe End.REPLACE SID cannot be the last segment in SRH or SR Policy.Any SID instance of this behavior is associated with a set, J, of one
or more L3 adjacencies of immediate BGP neighborsWhen Node N receives a packet destined to S and S is a locally
instantiated End.REPLACE SID, Node N executes the following procedure:For the use-case mentioned under END.REPLACEB6 SID is applicableThe End.REPLACEB6 SID cannot be the last segment in a SRH or SR Policy.Node N is configured with an IPv6 address T (e.g., assigned to its loopback).When Node N receives a packet destined to S and S is a locally
instantiated End.REPLACEB6 SID, Node N executes the following procedure:For the use-case mentioned under END.DB6 SID is applicable.The End.DB6 SID MUST be the last segment in SRH or SR Policy.Node N is configured with an IPv6 address T (e.g., assigned to its loopback).When Node N receives a packet destined to S and S is a locally
instantiated End.DB6 SID, Node N executes the following procedure:This document requires no IANA action.The authors will request an early allocation from the "SRv6 Endpoint
Behaviors" sub-registry of the "Segment Routing Parameters"
registry.Because SR inter-working requires co-operation between inter-working
domains, this document introduces no security consideration beyond those
addressed in , and
.Thanks to Ram Santhanakrishnan, Srihari Sangli, Rajendra Prasad Bollam
and Kiran Kushalad for their valuable comments.