[j-nsp] Explicit Null - IP/MPLS QoS

[Aaron]

Thanks Adam,

Cisco asr9k --------(sniffer)---------- juniper acx5048------------cisco
me3600(loopback 0 is 10.101.12.251)
ping 10.101.12.251 type 184 (executed on cli of 9k)
-----------------------------pinging----------------------------------------
--------------------->>>>

Q1 - If you have the sniffer between ASR and ACX can you see the EF markings
being copied into the EXP field?
A1 - Yes, ping from 9k to me3600 loopback shows on sniffer between 9k and
5048, that DSCP is 46 and MPLS EXP is 5
...furthermore, " ping 10.101.12.251" with no TYPE/DSCP specified then shows
the expected, DSCP0 and MPLS EXP 0

Yeah, there are some non-vpn things flowing through my mpls core like
management traffic that I need to deal with, which is exactly what I'm
testing...

So, it's interesting that dscp46/exp5 is seen on that 9k to 5048 link, but
with implicit-null php behavior from 5048 to 3600, the dscp is remarked to
0.  It seems that this behavior might be Uniform mode whereas the PHP
implicit null removal of that last label seems to be causing a zeroing-out
of the DSCP marking from 46 to 0.  Not sure if that uniform mode per se, but
I don't know what else to call it

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_te_diffserv/configuratio
n/15-mt/mp-te-diffserv-15-mt-book/mp-diffserv-tun-mode.pdf


- Aaron