[a-nsp] 7050SX MPLS ?

[Bryan Holloway]

Yeah, I may not have described this very well ...

( And thank you to Gert who indicated the same. :) )

Consider a 7050SX (PE) sitting downstream from an ASR9k (P). /30 between 
them running IS-IS.

Customer hangs off of a VLAN on the 7050SX. I can turn up MPLS/LDP just 
fine on the 7050 -- talks happily to the ASR -- but then I can't push 
full-payload packets (1500) to customer's VLAN from upstream RRs (or 
from anywhere, for that matter ...) Except from next-hop.

Spun up a vEOS running 4.25.0 and seeing the same behavior, but I 
honestly don't know what hardware it's trying to emulate ... (Thank you 
for that suggestion, Sabri, re: older firmware.)

Hope this better explains things ...

On 1/25/21 8:17 PM, steve ulrich wrote:
> bryan -
> 
> i'm not entirely clear as to what you're trying to do here.  when you're 
> talking about turning up MPLS/LDP between a pair of neighbors, i 
> assume one of these neighbors is the aforementioned 7050SX? (which has 
> pretty limited MPLS capabilities)  if so, i would expect that to have 
> limited/unpredictable results.  the control plane likely does its thing, 
> the linkages to the forwarding plane for the X-series is another matter.
> 
> your last paragraph is a reasonable summary of the state of things wrt 
> to X-series switches.  though there are some operations that are 
> supported. (see 
> https://eos.arista.com/eos-4-23-0f/mpls-support-on-x-series-switches/ 
> <https://eos.arista.com/eos-4-23-0f/mpls-support-on-x-series-switches/>)
> 
> 
> 
> On Mon, Jan 25, 2021 at 11:58 AM Bryan Holloway <bryan at shout.net 
> <mailto:bryan at shout.net>> wrote:
> 
>     I think I already know the answer to this, but here goes:
> 
>     Arista DCS-7050SX-64
>     Hardware version:    02.10
>     Software image version: 4.21.10M
> 
>     Was successful in turning up MPLS/LDP between a pair of neighbors no
>     problem.
> 
>     I can see the peers and addresses bound to those peers, etc.
> 
>     However, when I bring up BGP to a pair of upstream RRs, I run into MTU
>     issues. 1496 bytes (no DF) works fine; 1500 does not.
> 
>     As soon as I kill MPLS, it works.
> 
>       From the docs I've read and the usual Google-cranking, I get the
>     impression that the 7050 will happy "pass-through" MPLS traffic, but it
>     won't let you terminate anything on that particular L3 switch.
> 
>     Is that a correct assumption?
> 
>     Seems to work fine on the 7280s.
> 
>     Thank you all in advance,
> 
>                      - bryan
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> 
> -- 
> steve ulrich (sulrich at botwerks.*)