Arista EOS: RSVP related features

  References:

• https://eos.arista.com/eos-4-25-1f/rsvp-te-ler/
• https://eos.arista.com/eos-4-23-2f/rsvp-te-lsr/
• https://eos.arista.com/eos-4-23-1f/bgp-nexthop-resolution-ribs-evpn-and-ipv4-6-labeled-unicast-support/
• https://eos.arista.com/eos-4-22-1f/bgp-nexthop-resolution-ribs-mpls-vpn-support/
• https://eos.arista.com/eos-4-22-0f/user-defined-tunnel-ribs/

Arista EOS: %ETH-4-ERRDISABLE: no-internal-vlan error detected

If you are seeing the following error message 

Jan 12 19:03:19 sn452 Ebra: %ETH-4-ERRDISABLE: no-internal-vlan error detected on Ethernet81.

And the output of "show interface status" indicates some ethernet ports are error-disabled like

sn452.19:00:35(config-if-Et1-104)#show interfaces status errdisabled
   Port        Name             Status         Reason
----------- ---------------- ----------------- ----------------
   Et81                         errdisabled    no-internal-vlan
   Et82                         errdisabled    no-internal-vlan

The reason for the above error is that EOS running out of internal VLAN for routed ports. The EOS needs to assign an internal VLAN for the none switching ports. If you have the following 2 lines of configuration, you may hit this error

switchport default mode routed <<< all ports are routed
vlan internal order descending range 4001 4080 <<< but only 80 VLANs assigned

So the solution is to remove the internal VLAN range. 

Why unprotected ISIS segment routing prefix with TiLFA enabled

 

In the above topology, the output of "show isis segment-routing prefix" on PE11 shows the SID of PE22 is not protected. 

bn303-PEa1.23:58:00(config-router-isis-af)#show isis segment-routing prefix-segments

System ID: 0000.0000.0011 Instance: 'isis-sr'

SR supported Data-plane: MPLS SR Router ID: 200.250.250.1

Node: 10     Proxy-Node: 0      Prefix: 0       Total Segments: 10

Flag Descriptions: R: Re-advertised, N: Node Segment, P: no-PHP

                   E: Explicit-NULL, V: Value, L: Local

Segment status codes: * - Self originated Prefix, L1 - level 1, L2 - level 2

  Prefix                      SID Type       Flags                   System ID       Level Protection

  ------------------------- ----- ---------- ----------------------- --------------- ----- ----------

......

  100.250.250.22/32            22 Node       R:0 N:1 P:0 E:0 V:0 L:0 0000.0000.0022  L2    unprotected

  100.255.255.31/32            31 Node       R:0 N:1 P:0 E:0 V:0 L:0 0000.0000.0031  L2    node

The reason the SID of PE22 is "unprotected" is that the PE11 has a 2-way ECMP to the destination. 

bn303-PEa1.23:58:01(config-router-isis-af)#show ip route 100.250.250.22/32

 I L2     100.250.250.22/32 [115/50] via 100.2.11.0, Ethernet3/1/1

                                     via 100.1.11.0, Ethernet10/36/1

Now let's the shutdown the interface between PE11 and P2 to break this ECMP. Now the prefix-segment is proteced now. 

bn303-PEa1.00:14:21(config)#int e3/1/1

bn303-PEa1.00:14:27(config-if-Et3/1/1)#shu

bn303-PEa1.00:14:31#show ip route 100.250.250.22/32

 I L2     100.250.250.22/32 [115/50] via 100.1.11.0, Ethernet10/36/1

bn303-PEa1.00:14:34#show isis segment-routing prefix-segments

Segment status codes: * - Self originated Prefix, L1 - level 1, L2 - level 2

  Prefix                      SID Type       Flags                   System ID       Level Protection

  ------------------------- ----- ---------- ----------------------- --------------- ----- ----------

...

  100.250.250.22/32            22 Node       R:0 N:1 P:0 E:0 V:0 L:0 0000.0000.0022  L2    node

  100.255.255.31/32            31 Node       R:0 N:1 P:0 E:0 V:0 L:0 0000.0000.0031  L2    node