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--- network_stuff:arista:mpls [2022/04/28 11:17] – jotasandoku
+++ network_stuff:arista:mpls [2025/04/13 13:36] (current) – jotasandoku
@@ Line 2: / Line 2: @@
 TODO
 ----
-MPLS SEGMENT ROUTING NOTES (SR-MPLS NOTES)\\
+MPLS SEGMENT ROUTING NOTES (SRv6)
+\\
+think of SRv6–using IPv6 addresses as segment IDs, and breaking the least significant /64 to create microsids for service differentiation
+\\
 Is mostly MPLS but:
-  * labels are distributed in the IGP
+  * **labels** are distributed/encapsulated **in the IGP**
-  * labels are globally unique (not reused) so better control of the paths.
+  * labels are **globally unique** (not reused) so better control of the paths.
+Options:
+  * Control plane: ipv4 / ipv6
+  * Data plane: **mpls or native ipv6**
 ----
 MPLS FOR ARISTA:\\
@@ Line 82: / Line 91: @@
         neighbor 10.0.0.3 activate
         neighbor 10.0.0.3 encapsulation mpls next-hop-self source-interface Loopback0
+----
+__IMPLICIT/EXPLICIT NULL__
+\\
+  * This null label is always 'sent' by the PE as signalling to the PHP.
+    * implicit null is no signalling and letting the PHP do its thing and send the mpls label as an IP packet (no labels) towards the PE
+    * explicit null is the PHP sending the mpls packet with the last label as a 'dummy' one (value 0(2 in IPv6)). The advantage is that EXP and QoS values are preserved.
+----
+SHOW COMMANDS:
+\\
+  show ip bgp vrf red
+  show ip route vrf red | begin Gateway
+  show mpls lfib route    # arista only labels for lo. You'll only see transport labels here
+  show bgp vpn-ipv4 172.16.0.0/24 detail # this is for the vpnv4 of the customer prefix 172
+  !
+  pe1#show bgp vpn-ipv4 172.16.2.0/24 detail
+  BGP routing table information for VRF default
+  Router identifier 10.0.0.1, local AS number 65000
+  BGP routing table entry for IPv4 prefix 172.16.2.0/24, Route Distinguisher: 65000:2
+   Paths: 1 available
+    Local
+.0.0.2 from 10.0.0.2 (10.0.0.2)
+        Origin IGP, metric -, localpref 100, weight 0, valid, internal, best
+        Extended Community: Route-Target-AS:65000:2
+        Remote MPLS label: 100001    <<< the vpnv4 label for 172.16.2.0/24
+  !
+  traceroute mpls ldp ip 10.0.0.1/32    # this shows the swapping of the transport label
+  show mpls ldp neighbord    # luk lesson 2.3
+  show mpls ldp bindings     # luk lesson 2.3

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