BGP Segment Routing Using the Prefix SID Attribute
This chapter describes BGP Segment Routing using the prefix SID attribute.
Topics in this chapter include:
Applicability
The information and configuration in this chapter are based on SR Linux Release 25.10.R1. BGP Segment Routing (SR) is supported in SR Linux Release 24.10.R6, and later.
Overview
Segment Routing (SR) has become a foundational technology for Software-Defined Networking (SDN) in Wide Area Networks (WANs). Also, SR is being extended beyond WAN borders into Data Centers (DCs).
SR allows an ingress node to route a packet from the source, by prepending an SR header containing an ordered list of segment identifiers (SIDs). A SID represents a topological or service-based instruction. A SID can have a local meaning for one specific node, or a global meaning within the SR domain, such as the instruction to forward a packet on the Equal-Cost Multipath (ECMP) aware shortest path to reach some prefix.
In WAN networks, infrastructure IP reachability is nearly always conveyed by an IGP protocol, such as IS-IS and OSPF, but in large-scale DCs, BGP has become the protocol of choice. In a typical DC design, BGP is used for endpoint reachability, as follows:
Each node (Top of Rack (TOR), leaf, spine, and so on) has its own Autonomous System (AS).
Each node has an eBGP session to each of its directly connected peers.
Each node originates the IPv4 (or IPv6) address of its loopback interface into BGP and announces it to its neighbors.
To extend SR-MPLS into DCs that use this type of BGP design, the SR Linux nodes must advertise their loopback IP prefix in a BGP ipv4-labeled-unicast (BGP-LU) IPv4 route with a prefix SID attribute. The prefix SID attribute is ignored when attached to other types of BGP routes, including BGP-LU IPv6 routes, but it is still propagated.
A BGP prefix SID is always a global SID within the SR domain and identifies an instruction to forward the packet along the ECMP-aware BGP-computed best paths to reach the prefix. The BGP prefix SID attribute can also help to create SR paths that transit across multiple administrative domains that do not share IGP SR topology information.
BGP-LU IPv4 route with prefix SID BGP path attribute shows a node in AS 64501 advertising a BGP-LU IPv4 route for prefix 10.0.1.1/32 with SID 20101. The SR-capable nodes forward packets with SID 20101 via the best BGP path to 10.0.1.1, using any of the available multipaths computed by BGP.
The BGP prefix SID attribute is an optional and transitive BGP path attribute, meaning that the attribute is expected to be propagated by routers that do not recognize the type value. When SR is deployed using an MPLS dataplane (SR-MPLS), the BGP prefix SID encodes:
A 32-bit label-index Type-Length-Value (TLV) (mandatory TLV)
An originator Segment Routing Global Block (SRGB) TLV containing one or more SRGB fields (optional TLV). If the SRGB field occurs multiple times in the SRGB TLV, the SRGB space of the ingress node consists of multiple ranges that are concatenated.
BGP signaling overview shows that node PE-1 exports a BGP-LU IPv4 route with prefix 10.0.1.1/32 and label 20101. The BGP prefix SID attribute contains an SR label index of 101 and the originator SRGB with start label 20000 and size 1000 (from 20000 to 20999). Node PE-2 imports the BGP-LU IPv4 route and exports it to the next node.
To add, replace, or process a BGP prefix SID, SR must be administratively enabled in the bgp context. The BGP prefix SID range is equal to the SRGB that is also used by SR-ISIS or SR-OSPF and that is defined in the system mpls label-ranges context. All BGP prefix SID label values must reside within the global SRGB.
To originate BGP SR prefixes, two policies are required with action bgp label-allocation prefix-sid, which may or may not be identical:
export policy [<policy-name>] to advertise a prefix to a neighbor with an SR label index
- route-table-import <policy-name> used to populate a local BGP-SR table with an SR label index
In the example topology used in this chapter, the export policy and the route-table-import policy are identical and have an action entry with policy-result accept and bgp label-allocation prefix-sid, so on PE-1, the prefix SID for the prefix 10.0.1.1/32 equals 20101, which is the sum of the start label for the prefix SID range 20000 and the SR label index 101.
A unique SR label index value must be assigned to each different IPv4 prefix that is advertised with a BGP prefix SID. However, in case of a conflict with another SR-programmed Label Forwarding Instance Base (LFIB) entry, the conflict situation is addressed as follows:
If the conflict is with another BGP-LU IPv4 route for a different prefix with a prefix SID attribute, all the conflicting BGP-LU IPv4 routes for both prefixes are advertised with normal BGP-LU labels from the dynamic label range, not from the dedicated SR label range.
If the conflict is with an IGP route and the route-table-import policy action contains reuse-igp false in the bgp label-allocation prefix-sid command, the BGP-LU IPv4 route loses to the IGP route and is advertised with a normal BGP-LU label from the dynamic SR label range.
If the conflict is with an IGP route and the route-table-import policy action contains reuse-igp true in the bgp label-allocation prefix-sid command, this is not considered a conflict and BGP uses the IGP-signaled SR label index to derive its advertised label. This stitches the BGP SR tunnel to the IGP SR tunnel.
Stitching of SR-ISIS or SR-OSPF to SR-BGP is one of the main advantages of implementing SR-BGP.
Any /32 BGP-LU IPv4 route containing a prefix SID attribute is resolvable and usable in the same way as /32 BGP-LU IPv4 routes without prefix SID attribute. The routes can be installed in the route table and tunnel table, have ECMP next hops or FRR backup next hops, and can be used as transport tunnels.
Receiving a /32 BGP-LU IPv4 route with prefix SID attribute does not create a tunnel in the SR database; it only creates a label swap entry when the route is re-advertised with a new next hop. This means that the first SID in any SID list of an SR policy should not be based on a BGP prefix SID because the data path would not be programmed correctly. However, the BGP prefix SID can be used as a non-first SID in any SR policy.
Each node capable of receiving and propagating the BGP prefix SID attribute can be configured with the optional-attributes block-prefix-sid command at the BGP group or neighbor configuration levels to:
block the propagation of the attribute outside its local SR domain
block inbound propagation of the attribute from another SR domain
When optional-attributes block-prefix-sid applies to a BGP session, the prefix SID attribute is stripped from all sent and received routes on that session, even if the prefix SID attribute was added to the outbound routes by the local router. By default, this feature is not configured, so the prefix SID is propagated freely to and from all BGP peers.
Configuration
Example topology shows the example topology with four nodes in different ASs. The loopback addresses 10.0.1.1/32 on PE-1 and 10.0.4.1/32 on PE-4 are exported in BGP-LU IPv4 routes with prefix SID attribute.
The initial configuration includes:
cards, MDAs, ports
interfaces
PE-3 and PE-4 have ecmp and multipath ebgp max-paths set to 2 for BGP address family ipv4-labeled-unicast
No IGP is configured, so SR-ISIS or SR-OSPF cannot be used.
Configure eBGP
Configure eBGP on all PEs for the ipv4-labeled-unicast address family, as follows. PE-3 and PE-4 have multipath ebgp max-paths set to 2 for BGP address family ipv4-labeled-unicast.
# on all PEs:
enter candidate
network-instance default {
protocols {
bgp {
admin-state enable
autonomous-system 64501 # 64504 on PE-4
router-id 192.0.2.1 # 192.0.4.1 on PE-4
ebgp-default-policy {
import-reject-all false
export-reject-all false
}
afi-safi ipv4-labeled-unicast {
admin-state enable
multipath { # only between PE-3 and PE-4
ebgp {
maximum-paths 2
}
}
}
group grp-EBGP {
admin-state enable
}
neighbor 192.168.12.2 { # 192.168.34.1 and 192.168.34.5 on PE-4
admin-state enable
peer-as 64502 # 64503 on PE-4
peer-group grp-EBGP
}
}
}
}The configuration is similar on PE-2 and PE-3. PE-3 and PE-4 have two interfaces toward each other.
Configure BGP segment routing using prefix SID
Configure the SRGB and enable BGP SR on all PEs, as follows:
# on all PEs:
enter candidate
system {
mpls {
label-ranges {
static srgb-static {
shared true
start-label 20000
end-label 20999
}
}
}
}
network-instance default {
segment-routing {
mpls {
global-block {
label-range srgb-static
}
}
}
protocols {
bgp {
segment-routing-mpls {
admin-state enable
}
}
}
}Configure a loopback interface for network instance default, with IP address 10.0.1.1/32 on PE-1 and with IP address10.0.4.1/32 on PE-4, as follows:
# on PE-1, PE-4:
enter candidate
interface lo0 {
admin-state enable
subinterface 0 {
admin-state enable
ipv4 {
admin-state enable
address 10.0.1.1/32 { } # 10.0.4.1/32 on PE-4
}
}
}
network-instance default {
interface lo0.0 {
interface-ref {
interface lo0
subinterface 0
}
}
}Assign a local prefix SID label index ipv4-label-index to each loopback interface, as follows:
# on PE-1, PE-4:
enter candidate
network-instance default {
segment-routing {
mpls {
local-prefix-sid 1 {
interface lo0.0
ipv4-label-index 101 # 104 on PE-4
}
}
}
}Define policies with action bgp label-allocation prefix-sid for exporting and importing the prefixes. It is possible to define different policies for exporting and importing the prefixes. In this example, PE-1 and PE-4 have no explicit import policy. PE-1 an PE-4 each use a single policy as an export policy and as a route-table-import policy. Define the following policy on PE-1 for exporting prefix 10.0.1.1/32 and importing it in the local route table:
# on PE-1, PE-4:
enter candidate
routing-policy {
prefix-set ps-10 {
prefix 10.0.1.1/32 mask-length-range exact { } # 10.0.4.1/32 on PE-4
}
policy pol-10 {
statement 10 {
match {
prefix {
prefix-set ps-10
}
}
action {
policy-result accept
bgp {
label-allocation {
prefix-sid {
reuse-igp false
}
}
}
}
}
}
}Configure the export policy in the BGP group, as follows:
# on PE-1, PE-4:
enter candidate
network-instance default {
protocols {
bgp {
group grp-EBGP {
export-policy [ pol-10 ]
}
}
}
}Populate a local BGP-SR table for the ipv4-labeled-unicast address family with the route-table-import <policy-name> command in the bgp rib-management context, as follows:
# on PE-1, PE-4:
enter candidate
network-instance default {
protocols {
bgp {
rib-management {
table ipv4-labeled-unicast {
route-table-import pol-10
}
}
}
}
}As a result, PE-1 exports prefix 10.0.1.1/32 with SR label index 101, corresponding with a BGP prefix SID 20101 (start label 20000 + index 101 = 20101).
Likewise, PE-4 exports prefix 10.0.4.1/32 with SR label index 104, corresponding with a BGP prefix SID 20104 (start label 20000 + index 104 = 20104).
The following info from state commands display the BGP-SR table on the different PEs. Two labels are allocated from the SR label range on each PE.
PE-1 advertises SR label 20101 for its local prefix 10.0.1.1/32 to its neighbor on PE-2. PE-1 receives SR label 20104 for remote prefix 10.0.4.1/32 from its neighbor on PE-2.
A:admin@PE-1# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-out-post route * neighbor * path-id 0 | as table |filter fields attr-id advertised-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Advertised-mpls- |
| | | | | | | label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.12.2 | 0 | 65 | 20101 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-1# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-in-pre route * neighbor * path-id 0 | as table |filter fields attr-id received-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Received-mpls-label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.12.2 | 0 | 66 | 20104 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-1# info from state with-context / system mpls label-ranges static * | as table | filter fields *
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+
| Name | Shared | Start-label | End-label | Allocated-labels | Free-labels | Status |
+=================================================================+========+=============+===========+==================+=============+================+
| srgb-static | true | 20000 | 20999 | 2 | 998 | ready |
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+PE-2 receives SR label 20101 for remote prefix 10.0.1.1/32 from its neighbor on PE-1. PE-2 advertises that SR label 20101 to its neighbor on PE-3.
PE-2 receives SR label 20104 for remote prefix 10.0.4.1/32 from its neighbor on PE-3. PE-2 advertises that SR label 20104 to its neighbor on PE-1.
A:admin@PE-2# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-out-post route * neighbor * path-id 0 | as table |filter fields attr-id advertised-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Advertised-mpls- |
| | | | | | | label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.23.2 | 0 | 51 | 20101 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.12.1 | 0 | 53 | 20104 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-2# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-in-pre route * neighbor * path-id 0 | as table |filter fields attr-id received-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Received-mpls-label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.12.1 | 0 | 50 | 20101 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.23.2 | 0 | 52 | 20104 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-2# info from state with-context / system mpls label-ranges static * | as table | filter fields *
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+
| Name | Shared | Start-label | End-label | Allocated-labels | Free-labels | Status |
+=================================================================+========+=============+===========+==================+=============+================+
| srgb-static | true | 20000 | 20999 | 2 | 998 | ready |
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+Because PE-3 and PE-4 have BGP multipath configured, traffic flows can be sprayed over two links.
PE-3 receives SR label 20101 for remote prefix 10.0.1.1/32 from its neighbor on PE-2. PE-3 advertises that SR label 20101 to two neighbors on PE-4. PE-3 also receives SR label 20101 for remote prefix 10.0.1.1/32 from one neighbor on PE-4 but does not use it.
PE-3 receives SR label 20104 for remote prefix 10.0.4.1/32 from two neighbors on PE-4 but uses SR label 20104 from only one neighbor on PE-4. PE-3 advertises that SR label 20104 to its neighbor on PE-2 and to the other neighbor on PE-4.
A:admin@PE-3# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-out-post route * neighbor * path-id 0 | as table |filter fields attr-id advertised-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Advertised-mpls- |
| | | | | | | label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.34.2 | 0 | 67 | 20101 |
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.34.6 | 0 | 67 | 20101 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.23.1 | 0 | 71 | 20104 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.34.6 | 0 | 71 | 20104 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-3# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-in-pre route * neighbor * path-id 0 | as table |filter fields attr-id received-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Received-mpls-label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.23.1 | 0 | 66 | 20101 |
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.34.6 | 0 | 68 | 20101 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.34.2 | 0 | 70 | 20104 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.34.6 | 0 | 69 | 20104 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-3# info from state with-context / system mpls label-ranges static * | as table | filter fields *
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+
| Name | Shared | Start-label | End-label | Allocated-labels | Free-labels | Status |
+=================================================================+========+=============+===========+==================+=============+================+
| srgb-static | true | 20000 | 20999 | 2 | 998 | ready |
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+Because PE-3 and PE-4 have BGP multipath configured, traffic flows can be sprayed over two links.
PE-4 advertises SR label 20104 for its local prefix 10.0.4.1/32 to two neighbors on PE-3. PE-4 also receives SR label 20104 for its local prefix 10.0.4.1/32 from one neighbor on PE-3 but does not use it.
PE-4 receives SR label 20101 for remote prefix 10.0.1.1/32 from two neighbors on PE-3 but uses SR label 20101 from only one neighbor on PE-3. PE-4 advertises that SR label 20101 to the other neighbor on PE-3.
A:admin@PE-4# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-out-post route * neighbor * path-id 0 | as table |filter fields attr-id advertised-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Advertised-mpls- |
| | | | | | | label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.34.5 | 0 | 82 | 20101 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.34.1 | 0 | 84 | 20104 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.34.5 | 0 | 84 | 20104 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-4# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
ipv4-labeled-unicast rib-in-out rib-in-pre route * neighbor * path-id 0 | as table |filter fields attr-id received-mpls-label
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
| Network-instance | Afi-safi | Prefix | Neighbor | Path-id | Attr-id | Received-mpls-label |
+======================+======================+======================+======================+============+======================+======================+
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.34.1 | 0 | 83 | 20101 |
| default | ipv4-labeled-unicast | 10.0.1.1/32 | 192.168.34.5 | 0 | 81 | 20101 |
| default | ipv4-labeled-unicast | 10.0.4.1/32 | 192.168.34.5 | 0 | 85 | 20104 |
+----------------------+----------------------+----------------------+----------------------+------------+----------------------+----------------------+
A:admin@PE-4# info from state with-context / system mpls label-ranges static * | as table | filter fields *
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+
| Name | Shared | Start-label | End-label | Allocated-labels | Free-labels | Status |
+=================================================================+========+=============+===========+==================+=============+================+
| srgb-static | true | 20000 | 20999 | 2 | 998 | ready |
+-----------------------------------------------------------------+--------+-------------+-----------+------------------+-------------+----------------+The tunnel table on PE-1 shows that a BGP tunnel with ID 262145 is available toward destination 10.0.4.1/32:
A:admin@PE-1# show / network-instance default tunnel-table ipv4
--------------------------------------------------------------------------------------------------------------------------------------------------------
IPv4 tunnel table of network-instance "default"
--------------------------------------------------------------------------------------------------------------------------------------------------------
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
| IPv4 Prefix | Tunnel Type | Tunnel ID | FIB | Metric | Preference | Last Update | Backup | Next-hop | Next-hop |
| | | | | | | | Nexthops | (Type) | |
+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+
| 10.0.4.1/32 | bgp | 262145 | Y | 1000 | 12 | 2026-01- | | 192.168.12.2 | ethernet- |
| | | | | | | 21T22:09:31. | | (mpls) | 1/2.1 |
| | | | | | | 623Z | | | |
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 BGP tunnels, 1 active, 0 inactive
--------------------------------------------------------------------------------------------------------------------------------------------------------The detail provides more information on the label (20104) and the next hop (192.168.12.2):
A:admin@PE-1# show / network-instance default tunnel-table ipv4 detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for network instance "default" tunnel table
--------------------------------------------------------------------------------------------------------------------------------------------------------
========================================================================================================================================================
Destination : 10.0.4.1/32
Tunnel Type : bgp
Tunnel ID : 262145
Metric : 1000
Preference : 12
Last Update : 2026-01-21T22:09:31.623Z
FIB Status : active
Next-hops
192.168.12.2 (mpls) via [ethernet-1/2.1]
pushed MPLS labels : [20104]
========================================================================================================================================================On PE-2, two BGP tunnels are available: one toward destination 10.0.1.1/32 with SR label 20101 and another toward destination 10.0.4.1/32 with SR label 20104:
A:admin@PE-2# show / network-instance default tunnel-table ipv4
--------------------------------------------------------------------------------------------------------------------------------------------------------
IPv4 tunnel table of network-instance "default"
--------------------------------------------------------------------------------------------------------------------------------------------------------
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
| IPv4 Prefix | Tunnel Type | Tunnel ID | FIB | Metric | Preference | Last Update | Backup | Next-hop | Next-hop |
| | | | | | | | Nexthops | (Type) | |
+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+
| 10.0.1.1/32 | bgp | 262145 | Y | 1000 | 12 | 2026-01- | | 192.168.12.1 | ethernet- |
| | | | | | | 21T22:09:09. | | (mpls) | 1/1.1 |
| | | | | | | 618Z | | | |
| 10.0.4.1/32 | bgp | 262146 | Y | 1000 | 12 | 2026-01- | | 192.168.23.2 | ethernet- |
| | | | | | | 21T22:09:30. | | (mpls) | 1/3.1 |
| | | | | | | 161Z | | | |
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
2 BGP tunnels, 2 active, 0 inactive
--------------------------------------------------------------------------------------------------------------------------------------------------------
A:admin@PE-2# show / network-instance default tunnel-table ipv4 detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for network instance "default" tunnel table
--------------------------------------------------------------------------------------------------------------------------------------------------------
========================================================================================================================================================
Destination : 10.0.1.1/32
Tunnel Type : bgp
Tunnel ID : 262145
Metric : 1000
Preference : 12
Last Update : 2026-01-21T22:09:09.618Z
FIB Status : active
Next-hops
192.168.12.1 (mpls) via [ethernet-1/1.1]
pushed MPLS labels : [20101]
========================================================================================================================================================
Destination : 10.0.4.1/32
Tunnel Type : bgp
Tunnel ID : 262146
Metric : 1000
Preference : 12
Last Update : 2026-01-21T22:09:30.161Z
FIB Status : active
Next-hops
192.168.23.2 (mpls) via [ethernet-1/3.1]
pushed MPLS labels : [20104]
========================================================================================================================================================On PE-3, two BGP tunnels are available: one toward destination 10.0.1.1/32 with SR label 20101 and one toward destination 10.0.4.1/32 with SR label 20104. The BGP tunnel toward destination 10.0.4.1/32 has two next hops.
A:admin@PE-3# show / network-instance default tunnel-table ipv4
--------------------------------------------------------------------------------------------------------------------------------------------------------
IPv4 tunnel table of network-instance "default"
--------------------------------------------------------------------------------------------------------------------------------------------------------
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
| IPv4 Prefix | Tunnel Type | Tunnel ID | FIB | Metric | Preference | Last Update | Backup | Next-hop | Next-hop |
| | | | | | | | Nexthops | (Type) | |
+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+
| 10.0.1.1/32 | bgp | 262145 | Y | 1000 | 12 | 2026-01- | | 192.168.23.1 | ethernet- |
| | | | | | | 21T22:09:25. | | (mpls) | 1/2.1 |
| | | | | | | 951Z | | | |
| 10.0.4.1/32 | bgp | 262146 | Y | 1000 | 12 | 2026-01- | | 192.168.34.2 | ethernet- |
| | | | | | | 21T22:09:27. | | (mpls) | 1/4.1 |
| | | | | | | 953Z | | | |
| | | | | | | | | 192.168.34.6 | ethernet- |
| | | | | | | | | (mpls) | 1/6.1 |
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
2 BGP tunnels, 2 active, 0 inactive
--------------------------------------------------------------------------------------------------------------------------------------------------------
A:admin@PE-3# show / network-instance default tunnel-table ipv4 detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for network instance "default" tunnel table
--------------------------------------------------------------------------------------------------------------------------------------------------------
========================================================================================================================================================
Destination : 10.0.1.1/32
Tunnel Type : bgp
Tunnel ID : 262145
Metric : 1000
Preference : 12
Last Update : 2026-01-21T22:09:25.951Z
FIB Status : active
Next-hops
192.168.23.1 (mpls) via [ethernet-1/2.1]
pushed MPLS labels : [20101]
========================================================================================================================================================
Destination : 10.0.4.1/32
Tunnel Type : bgp
Tunnel ID : 262146
Metric : 1000
Preference : 12
Last Update : 2026-01-21T22:09:27.953Z
FIB Status : active
Next-hops
192.168.34.2 (mpls) via [ethernet-1/4.1]
pushed MPLS labels : [20104]
192.168.34.6 (mpls) via [ethernet-1/6.1]
pushed MPLS labels : [20104]
========================================================================================================================================================On PE-4, one BGP tunnel is available toward destination 10.0.1.1/32 with SR label 20101. The BGP tunnel toward destination 10.0.1.1/32 has two next hops.
A:admin@PE-4# show / network-instance default tunnel-table ipv4
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
| IPv4 Prefix | Tunnel Type | Tunnel ID | FIB | Metric | Preference | Last Update | Backup | Next-hop | Next-hop |
| | | | | | | | Nexthops | (Type) | |
+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+
| 10.0.1.1/32 | bgp | 262145 | Y | 1000 | 12 | 2026-01- | | 192.168.34.1 | ethernet- |
| | | | | | | 21T22:09:17. | | (mpls) | 1/3.1 |
| | | | | | | 151Z | | | |
| | | | | | | | | 192.168.34.5 | ethernet- |
| | | | | | | | | (mpls) | 1/5.1 |
+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 BGP tunnels, 1 active, 0 inactive
--------------------------------------------------------------------------------------------------------------------------------------------------------
A:admin@PE-4# show / network-instance default tunnel-table ipv4 detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for network instance "default" tunnel table
--------------------------------------------------------------------------------------------------------------------------------------------------------
========================================================================================================================================================
Destination : 10.0.1.1/32
Tunnel Type : bgp
Tunnel ID : 262145
Metric : 1000
Preference : 12
Last Update : 2026-01-21T22:09:17.151Z
FIB Status : active
Next-hops
192.168.34.1 (mpls) via [ethernet-1/3.1]
pushed MPLS labels : [20101]
192.168.34.5 (mpls) via [ethernet-1/5.1]
pushed MPLS labels : [20101]
========================================================================================================================================================PE-1 advertises a BGP-LU IPv4 route for prefix 10.0.1.1/32 with label 20101 to PE-2. The following command on PE-2 shows the received route:
A:admin@PE-2# show / network-instance default protocols bgp routes ipv4-labeled-unicast prefix 10.0.1.1/32
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for the BGP routes to network "10.0.1.1/32" network-instance "default"
--------------------------------------------------------------------------------------------------------------------------------------------------------
Network: 10.0.1.1/32
Received Paths: 1
Path 1: <Best,Valid,Used,>
Route source : neighbor 192.168.12.1
Route Preference: MED is -, No LocalPref
BGP next-hop : 192.168.12.1
Path : i [64501]
Communities : None
Path 1 was advertised to:
[ 192.168.23.2 ]
--------------------------------------------------------------------------------------------------------------------------------------------------------The detail shows the label, as follows:
A:admin@PE-2# show / network-instance default protocols bgp routes ipv4-labeled-unicast prefix 10.0.1.1/32 detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for the BGP routes to network "10.0.1.1/32" network-instance "default"
--------------------------------------------------------------------------------------------------------------------------------------------------------
Network: 10.0.1.1/32
Received Paths: 1
Path 1: <Best,Valid,Used,>
Route source : neighbor 192.168.12.1
Route Preference : MED is -, No LocalPref
BGP next-hop : 192.168.12.1
Path : i [64501]
Received Label : [20101]
Communities : None
RR Attributes : No Originator-ID, Cluster-List is [ - ]
Aggregation : Not an aggregate route
Unknown Attr : None
Invalid Reason : None
Tie Break Reason : none
Route Flap Damping: None
Path 1 was advertised to:
[ 192.168.23.2 ]
Route Preference: MED is -, No LocalPref
Path : i [64502, 64501]
Communities : None
RR Attributes : No Originator-ID, Cluster-List is [ - ]
Aggregation : Not an aggregate route
Unknown Attr : None
--------------------------------------------------------------------------------------------------------------------------------------------------------PE-2 advertises this route to PE-3 and PE-3 advertises it further to PE-4. The following command on PE-4 shows two BGP-LU IPv4 routes for prefix 10.0.1.1/32 with label 20101: one with next hop 192.168.34.1 and another one with next hop 192.168.34.5.
A:admin@PE-4# show / network-instance default protocols bgp routes ipv4-labeled-unicast prefix 10.0.1.1/32
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for the BGP routes to network "10.0.1.1/32" network-instance "default"
--------------------------------------------------------------------------------------------------------------------------------------------------------
Network: 10.0.1.1/32
Received Paths: 2
Path 1: <Best,Valid,Used,>
Route source : neighbor 192.168.34.1
Route Preference: MED is -, No LocalPref
BGP next-hop : 192.168.34.1
Path : i [64503, 64502, 64501]
Communities : None
Path 2: <Best,Valid,Used,>
Route source : neighbor 192.168.34.5
Route Preference: MED is -, No LocalPref
BGP next-hop : 192.168.34.5
Path : i [64503, 64502, 64501]
Communities : None
Path 2 was advertised to:
[ 192.168.34.5 ]
--------------------------------------------------------------------------------------------------------------------------------------------------------The detailed output for the BGP-LU IPv4 routes on PE-4 shows the label, as follows:
A:admin@PE-4# show / network-instance default protocols bgp routes ipv4-labeled-unicast prefix 10.0.1.1/32 detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Show report for the BGP routes to network "10.0.1.1/32" network-instance "default"
--------------------------------------------------------------------------------------------------------------------------------------------------------
Network: 10.0.1.1/32
Received Paths: 2
Path 1: <Best,Valid,Used,>
Route source : neighbor 192.168.34.1
Route Preference : MED is -, No LocalPref
BGP next-hop : 192.168.34.1
Path : i [64503, 64502, 64501]
Received Label : [20101]
Communities : None
RR Attributes : No Originator-ID, Cluster-List is [ - ]
Aggregation : Not an aggregate route
Unknown Attr : None
Invalid Reason : None
Tie Break Reason : none
Route Flap Damping: None
Path 2: <Best,Valid,Used,>
Route source : neighbor 192.168.34.5
Route Preference : MED is -, No LocalPref
BGP next-hop : 192.168.34.5
Path : i [64503, 64502, 64501]
Received Label : [20101]
Communities : None
RR Attributes : No Originator-ID, Cluster-List is [ - ]
Aggregation : Not an aggregate route
Unknown Attr : None
Invalid Reason : None
Tie Break Reason : peer-ip
Route Flap Damping: None
Path 2 was advertised to:
[ 192.168.34.5 ]
Route Preference: MED is -, No LocalPref
Path : i [64504, 64503, 64502, 64501]
Communities : None
RR Attributes : No Originator-ID, Cluster-List is [ - ]
Aggregation : Not an aggregate route
Unknown Attr : None
--------------------------------------------------------------------------------------------------------------------------------------------------------The route table for network instance default on PE-4 is as follows. It shows that prefix 10.0.1.1/32 has two active ECMP routes (two next hops).
A:admin@PE-4# show / network-instance default route-table ipv4-unicast summary
--------------------------------------------------------------------------------------------------------------------------------------------------------
IPv4 unicast route table of network instance default
--------------------------------------------------------------------------------------------------------------------------------------------------------
+----------------+------+-----------+--------------------+---------+---------+--------+-----------+-----------+-----------+-----------+-----------+
| Prefix | ID | Route | Route Owner | Active | Origin | Metric | Pref | Next-hop | Next-hop | Backup | Backup |
| | | Type | | | Network | | | (Type) | Interface | Next-hop | Next-hop |
| | | | | | Instanc | | | | | (Type) | Interface |
| | | | | | e | | | | | | |
+================+======+===========+====================+=========+=========+========+===========+===========+===========+===========+===========+
| 10.0.1.1/32 | 0 | bgp-label | bgp_label_mgr | True | default | 0 | 170 | 192.168.3 | ethernet- | | |
| | | | | | | | | 4.1 | 1/3.1 | | |
| | | | | | | | | (mpls) | ethernet- | | |
| | | | | | | | | 192.168.3 | 1/5.1 | | |
| | | | | | | | | 4.5 | | | |
| | | | | | | | | (mpls) | | | |
| 10.0.4.1/32 | 14 | host | net_inst_mgr | True | default | 0 | 0 | None | None | | |
| 192.0.2.4/32 | 13 | host | net_inst_mgr | True | default | 0 | 0 | None | None | | |
| 192.168.34.0/3 | 11 | local | net_inst_mgr | True | default | 0 | 0 | 192.168.3 | ethernet- | | |
| 0 | | | | | | | | 4.2 | 1/3.1 | | |
| | | | | | | | | (direct) | | | |
| 192.168.34.2/3 | 11 | host | net_inst_mgr | True | default | 0 | 0 | None | None | | |
| 2 | | | | | | | | | | | |
| 192.168.34.3/3 | 11 | host | net_inst_mgr | True | default | 0 | 0 | None | None | | |
| 2 | | | | | | | | | | | |
| 192.168.34.4/3 | 12 | local | net_inst_mgr | True | default | 0 | 0 | 192.168.3 | ethernet- | | |
| 0 | | | | | | | | 4.6 | 1/5.1 | | |
| | | | | | | | | (direct) | | | |
| 192.168.34.6/3 | 12 | host | net_inst_mgr | True | default | 0 | 0 | None | None | | |
| 2 | | | | | | | | | | | |
| 192.168.34.7/3 | 12 | host | net_inst_mgr | True | default | 0 | 0 | None | None | | |
| 2 | | | | | | | | | | | |
+----------------+------+-----------+--------------------+---------+---------+--------+-----------+-----------+-----------+-----------+-----------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
IPv4 routes total : 9
IPv4 prefixes with active routes : 9
IPv4 prefixes with active ECMP routes: 1
--------------------------------------------------------------------------------------------------------------------------------------------------------The following info from state commands show how the prefix SID attribute is advertised in BGP:
A:admin@PE-1# info from state with-context / network-instance default bgp-rib afi-safi ipv4-labeled-unicast
network-instance default {
bgp-rib {
afi-safi ipv4-labeled-unicast {
ipv4-labeled-unicast {
---snip---
rib-in-out {
---snip---
rib-out-post {
route 10.0.1.1/32 neighbor 192.168.12.2 path-id 0 {
attr-id 65
advertised-mpls-label [
20101
]
}
}
}
}
}
}
}
A:admin@PE-1# info from state with-context / network-instance default bgp-rib attr-sets attr-set *
network-instance default {
bgp-rib {
attr-sets {
---snip---
attr-set 65 {
---snip---
prefix-sid {
tlv label-index {
label-index {
label-index 101
}
}
tlv srgb-originator {
srgb-originator {
srgb [
20000:1000
]
}
}
}
}
}
}
}The following show command gives information about the BGP session establishment. Only the ipv4-labeled-unicast address family (via inheritance from the BGP level) is configured for BGP group grp-EBGP.
A:admin@PE-4# show / network-instance default protocols bgp neighbor *
--------------------------------------------------------------------------------------------------------------------------------------------------------
BGP neighbor summary for network-instance "default"
Flags: S static, D dynamic, L discovered by LLDP, B BFD enabled, - disabled, * slow
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
+-----------------+------------------------+-----------------+------+---------+--------------+--------------+------------+------------------------+
| Net-Inst | Peer | Group | Flag | Peer-AS | State | Uptime | AFI/SAFI | [Rx/Active/Tx] |
| | | | s | | | | | |
+=================+========================+=================+======+=========+==============+==============+============+========================+
| default | 192.168.34.1 | grp-EBGP | S | 64503 | established | 0d:0h:10m:39 | ipv4- | [1/1/1] |
| | | | | | | s | labeled- | |
| | | | | | | | unicast | |
| default | 192.168.34.5 | grp-EBGP | S | 64503 | established | 0d:0h:10m:39 | ipv4- | [2/1/2] |
| | | | | | | s | labeled- | |
| | | | | | | | unicast | |
+-----------------+------------------------+-----------------+------+---------+--------------+--------------+------------+------------------------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
Summary:
2 configured neighbors, 2 configured sessions are established, 0 disabled peers
0 dynamic peersThe following show command gives more detailed information per BGP group neighbor:
A:admin@PE-4# show / network-instance default protocols bgp neighbor * detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Peer : 192.168.34.1, remote AS: 64503, local AS: 64504, peer-type : ebgp
Type : static
Description : None
Group : grp-EBGP
Export policies : ['pol-10']
Import policies: []
---snip---
Admin-state is enable, session-state is established, up for 0d:0h:10m:39s
TCP connection is 192.168.34.2 [179] -> 192.168.34.1 [44365]
---snip---
Ipv4-labeled-unicast AFI/SAFI
End of RIB : sent, received
Received routes : 1
Rejected routes : None
Active routes : 1
Advertised routes : 1
Prefix-limit-received : None
Prefix-limit-accepted : None
Default originate : disabled
Advertise with IPv6 next-hops : False
Peer requested GR helper : None
Peer preserved forwarding state: None
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Peer : 192.168.34.5, remote AS: 64503, local AS: 64504, peer-type : ebgp
Type : static
Description : None
Group : grp-EBGP
Export policies : ['pol-10']
Import policies: []
---snip---
Admin-state is enable, session-state is established, up for 0d:0h:10m:39s
TCP connection is 192.168.34.6 [179] -> 192.168.34.5 [41361]
---snip---
Ipv4-labeled-unicast AFI/SAFI
---snip---
--------------------------------------------------------------------------------------------------------------------------------------------------------Configure an IP VRF
Example topology with network instance IP-VRF shows the example topology with a basic IP VRF to demonstrate the end-to-end control plane signaling and data plane verification.
Configure an eBGP multi-hop session for address family l3vpn-ipv4-unicast between the GRT loopback addresses 10.0.1.1/32 on PE-1 and 10.0.4.1/32 on PE-4. The additional BGP configuration is as follows:
# on PE-1, PE-4:
enter candidate
network-instance default {
protocols {
bgp {
group grp-EBGP-VPN {
admin-state enable
afi-safi l3vpn-ipv4-unicast {
admin-state enable
}
}
neighbor 10.0.4.1 { # 10.0.1.1 on PE-4
admin-state enable
peer-as 64504 # 64501 on PE-4
peer-group grp-EBGP-VPN
multihop {
admin-state enable
maximum-hops 64
}
transport {
local-address 10.0.1.1 # 10.0.4.1 on PE-4
}
}
}
}
}Configure a dynamic label range for non-default network instances on all PEs, as follows:
# on all PEs:
enter candidate
system {
mpls {
label-ranges {
dynamic dynamic-vrfs {
start-label 40000
end-label 40099
}
}
services {
network-instance {
dynamic-label-block dynamic-vrfs
}
}
}In addition, configure a loopback interface for network instance IP-VRF, with IP address 172.16.1.1/32 on PE-1 and with IP address 172.16.4.1/32 on PE-4, as follows:
# on PE-1, PE-4:
enter candidate
interface lo0 {
admin-state enable
subinterface 1 {
admin-state enable
description "loopback interface in IP-VRF"
ipv4 {
admin-state enable
address 172.16.1.1/32 { # 172.16.4.1/32 on PE-4
primary
}
}
}
}
network-instance IP-VRF {
type ip-vrf
admin-state enable
router-id 10.0.1.1 # 10.0.4.1 on PE-4
interface lo0.1 {
interface-ref {
interface lo0
subinterface 1
}
}Configure BGP VPN and BGP IP VPN with ecmp 2 and allowed-tunnel-types [ bgp ] for network instance IP-VRF, as follows:
# on PE-1, PE-4:
enter candidate
network-instance IP-VRF {
protocols {
bgp-ipvpn {
bgp-instance 1 {
admin-state enable
ecmp 2
mpls {
next-hop-resolution {
allowed-tunnel-types [ bgp ]
}
}
}
}
bgp-vpn {
bgp-instance 1 {
route-distinguisher {
rd 10.0.1.1:0 # 10.0.4.1:0 on PE-4
}
route-target {
export-rt target:64501:0 # target:64504:0 on PE-4
import-rt target:64504:0 # target:64501:0 on PE-4
}
}
}
}
}PE-1 receives the following l3vpn-ipv4-unicast route:
A:admin@PE-1# show / network-instance default protocols bgp neighbor 10.0.4.1 received-routes l3vpn-ipv4-unicast
--------------------------------------------------------------------------------------------------------------------------------------------------------
Peer : 10.0.4.1, remote AS: 64504, local AS: 64501
Type : static
Description : None
Group : grp-EBGP-VPN
--------------------------------------------------------------------------------------------------------------------------------------------------------
Status codes: u=used, *=valid, >=best, x=stale, b=backup, w=unused-weight-only
Origin codes: i=IGP, e=EGP, ?=incomplete
+-----------------------------------------------------------------------------------------------------------------------------------------------+
| Status Route- Network Path-id Next Hop MED LocPref AsPath Origin |
| distinguisher |
+===============================================================================================================================================+
| u*> 10.0.4.1:0 172.16.4.1/32 0 10.0.4.1 - [64504] i |
+-----------------------------------------------------------------------------------------------------------------------------------------------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 received BGP routes : 1 used 1 valid
--------------------------------------------------------------------------------------------------------------------------------------------------------The route table for IP-VRF on PE-1 is as follows:
A:admin@PE-1# network-instance IP-VRF route-table ipv4-unicast summary
--------------------------------------------------------------------------------------------------------------------------------------------------------
IPv4 unicast route table of network instance IP-VRF
--------------------------------------------------------------------------------------------------------------------------------------------------------
+----------------+------+-----------+--------------------+---------+---------+--------+-----------+-----------+-----------+-----------+-----------+
| Prefix | ID | Route | Route Owner | Active | Origin | Metric | Pref | Next-hop | Next-hop | Backup | Backup |
| | | Type | | | Network | | | (Type) | Interface | Next-hop | Next-hop |
| | | | | | Instanc | | | | | (Type) | Interface |
| | | | | | e | | | | | | |
+================+======+===========+====================+=========+=========+========+===========+===========+===========+===========+===========+
| 172.16.1.1/32 | 12 | host | net_inst_mgr | True | IP-VRF | 0 | 0 | None | None | | |
| 172.16.4.1/32 | 0 | bgp-ipvpn | bgp_ipvpn_mgr | True | IP-VRF | 1000 | 170 | 10.0.4.1/ | | | |
| | | | | | | | | 32 (indir | | | |
| | | | | | | | | ect/bgp) | | | |
+----------------+------+-----------+--------------------+---------+---------+--------+-----------+-----------+-----------+-----------+-----------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
IPv4 routes total : 2
IPv4 prefixes with active routes : 2
IPv4 prefixes with active ECMP routes: 0
--------------------------------------------------------------------------------------------------------------------------------------------------------The following show command gives information about the BGP session establishment. Both the ipv4-labeled-unicast (via inheritance from the BGP level) and l3vpn-ipv4-unicast address families are configured for BGP group grp-EBGP-VPN.
A:admin@PE-4# show / network-instance default protocols bgp neighbor *
--------------------------------------------------------------------------------------------------------------------------------------------------------
BGP neighbor summary for network-instance "default"
Flags: S static, D dynamic, L discovered by LLDP, B BFD enabled, - disabled, * slow
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
+-----------------+------------------------+-----------------+------+---------+--------------+--------------+------------+------------------------+
| Net-Inst | Peer | Group | Flag | Peer-AS | State | Uptime | AFI/SAFI | [Rx/Active/Tx] |
| | | | s | | | | | |
+=================+========================+=================+======+=========+==============+==============+============+========================+
| default | 10.0.1.1 | grp-EBGP-VPN | S | 64501 | established | 0d:0h:8m:19s | ipv4- | [1/0/1] |
| | | | | | | | labeled- | [1/1/1] |
| | | | | | | | unicast | |
| | | | | | | | l3vpn-ipv4 | |
| | | | | | | | -unicast | |
| default | 192.168.34.1 | grp-EBGP | S | 64503 | established | 0d:0h:24m:38 | ipv4- | [1/1/1] |
| | | | | | | s | labeled- | |
| | | | | | | | unicast | |
| default | 192.168.34.5 | grp-EBGP | S | 64503 | established | 0d:0h:24m:38 | ipv4- | [2/1/2] |
| | | | | | | s | labeled- | |
| | | | | | | | unicast | |
+-----------------+------------------------+-----------------+------+---------+--------------+--------------+------------+------------------------+
--------------------------------------------------------------------------------------------------------------------------------------------------------
Summary:
3 configured neighbors, 3 configured sessions are established, 0 disabled peers
0 dynamic peersThe following show command gives more detailed information per BGP neighbor:
A:admin@PE-4# show / network-instance default protocols bgp neighbor * detail
--------------------------------------------------------------------------------------------------------------------------------------------------------
Peer : 10.0.1.1, remote AS: 64501, local AS: 64504, peer-type : ebgp
Type : static
Description : None
Group : grp-EBGP-VPN
Export policies : []
Import policies: []
---snip---
Admin-state is enable, session-state is established, up for 0d:0h:8m:19s
TCP connection is 10.0.4.1 [179] -> 10.0.1.1 [38165]
---snip---
L3vpn-ipv4-unicast AFI/SAFI
End of RIB : sent, received
Received routes : 1
Rejected routes : None
Active routes : 1
Advertised routes : 1
Prefix-limit-received : 4294967295 routes, warning at 90, prevent-teardown False
Prefix-limit-accepted : None
Default originate : disabled
Advertise with IPv6 next-hops : False
Peer requested GR helper : None
Peer preserved forwarding state: None
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ipv4-labeled-unicast AFI/SAFI
End of RIB : sent, received
Received routes : 1
Rejected routes : None
Active routes : None
Advertised routes : 1
Prefix-limit-received : None
Prefix-limit-accepted : None
Default originate : disabled
Advertise with IPv6 next-hops : False
Peer requested GR helper : None
Peer preserved forwarding state: None
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Peer : 192.168.34.1, remote AS: 64503, local AS: 64504, peer-type : ebgp
Type : static
Description : None
Group : grp-EBGP
Export policies : ['pol-10']
Import policies: []
---snip---
Admin-state is enable, session-state is established, up for 0d:0h:24m:38s
TCP connection is 192.168.34.2 [179] -> 192.168.34.1 [44365]
---snip---
Ipv4-labeled-unicast AFI/SAFI
---snip---
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Peer : 192.168.34.5, remote AS: 64503, local AS: 64504, peer-type : ebgp
Type : static
Description : None
Group : grp-EBGP
Export policies : ['pol-10']
Import policies: []
---snip---
Admin-state is enable, session-state is established, up for 0d:0h:24m:38s
TCP connection is 192.168.34.6 [179] -> 192.168.34.5 [41361]
---snip---
Ipv4-labeled-unicast AFI/SAFI
---snip---
--------------------------------------------------------------------------------------------------------------------------------------------------------Conclusion
With BGP SR, it is possible to use SR without the use of an IGP protocol (for example, to cross AS boundaries). It is also possible to stitch SR-IGP and SR-BGP tunnels together. BGP SR uses the prefix SID attribute.