Differences

This shows you the differences between two versions of the page.

--- network_stuff:arista:mpls [2022/03/21 18:39] – jotasandoku
+++ network_stuff:arista:mpls [2025/04/13 13:36] (current) – jotasandoku
@@ Line 1: / Line 1: @@
+MPLS NOTES\\
+TODO
+----
+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/encapsulated **in the IGP**
+  * 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:\\
 Review limitations [[https://www.arista.com/en/um-eos/eos-bgpmpls-l3-vpn#xx1221179|here]] specially regarding **next-hop-self in RR topologies**.
@@ Line 45: / Line 64: @@
         redistribute ospf
+!! P CONFIGURATION
+configure terminal
+  ! note we don't need to enable ldp in each interface individually
+  interface Loopback0
+  mpls ip
+  mpls ldp
+  router-id interface Loopback0
+  no shutdown
 !! ROUTE REFLECTOR:
   router bgp 65000
@@ Line 52: / Line 80: @@
      bgp advertise-inactive
      neighbor 10.0.0.2 remote-as 65000
-     neighbor 10.0.0.2 next-hop-self
+     ! neighbor 10.0.0.2 next-hop-self
      neighbor 10.0.0.2 update-source Loopback0
      neighbor 10.0.0.2 description rr2
@@ Line 61: / Line 89: @@
      !
      address-family vpn-ipv4
-        neighbor 10.0.0.2 activate
+        neighbor 10.0.0.3 activate
-        neighbor 10.0.0.2 encapsulation mpls next-hop-self source-interface Loopback0
+        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

dokucama

User Tools

Site Tools

Differences

Page Tools