[j-nsp] Inter-AS MPLS OptB Endianness Issue?

[James Bensley]

Hi all,

Just noticed this the lab that between an ASR9K (5.3.3) and MX480
(13.3R8.7), nothing "major" as it work but just curious is anyone else
has seen this (especially between two MXs), I haven't.

On the MX the RD for the ABC VRF was set to "route-distinguisher
196744L:200;" and the RT is "196744:200". On the 9K it shows this:

show bgp vpnv4 unicast nei 172.31.98.77 routes
....
Route Distinguisher: 2281702144:200
*> 2.2.2.2/32         172.31.98.77                           0 196744 i

When I change the RD on the ABC VRF to "route-distinguisher
172.31.96.7:200; ", the ASR 9K shows this...

show bgp vpnv4 unicast nei 172.31.98.77 routes
....
Route Distinguisher: 172.31.96.7:200
*> 2.2.2.2/32         172.31.98.77                           0 196744 i


In either case it "works", the routes are received and installed as
expected (ultimately the RTs match up on either side), so perhaps not
really an issue, but a bit weird. It looks to me like a bug on the
Juniper when using 32B ASN for RDs when you specific the L option in
the RD [type 2] (or in the way the 9K interprets it?).


196744 in binary is:
0000 0000 0000 0011 0000 0000 1000 1000

2281702144 in binary is:
1000 1000 0000 0000 0000 0011 0000 0000

When sending a 32 bit administrator value for the RD, instead of the
16 bit one, the 2nd two bytes have come first and are back to front.
The first 2 bytes have come last but slightly bit-shifted. So is this
a big-endian / little-endian, network-to-host / host-to-network
mistake or am I reading into that too much? :)

Cheers,
James.