[c-nsp] multicast NOT in HW on 7600

[Liviu Pislaru]

hi

i have a multicast problem in the following topology;

TOPOLOGY:
Msource -> R1(SVI 10) ---trunk--- (SVI 10) R2 ---routed--- R3 ......Rn ...
Receiver

- R1(7613), R2(7609), R(7613) / IOS SRA3 / WS-SUP720-3BXL
- 10G link between them in WS-X6704-10GE linecards with DFC
- trunk between R1 and R2, link routed between R2 and R3
- SVI 10 has "ip pim sparse-mode" and "mpls ip" so R1 is PE router and R2,R3
...Rn are P routers.
- routed links between P routers has "ip pim sparse-mode" and "mpls ip"
- Msource (multicast source) interface from R1(routed) is configured in vrf
XXX
- BGP address-family ipv4 mdt configured on R1 (and all other PE)

PROBLEM:
all multicast traffic goes to RP on R2 (is software processed), CPU load
increase, etc ...

although all 76xx (P routers) are identically configured (regarding
multicast), on R2
(the one with the problem) we could NOT see this line:

P-router#sh mls ip multicast summary | i mvpn
Hardware shortcuts for mvpn mroutes supported

WORKAROUND:

Suspecting that "ip pim" on SVI might be the problem, i've changed the
topology with a routed link
between R1 and R3 and the problem was solved.

NEW TOPOLOGY:
Msource -> R1 ---routed--- R3 ......Rn ... Receiver

Unfortunatelly, i could not afford to change the link between R1 and R2 from
trunk to routed and keep R2
with multicast traffic flowing through it.


Have anybody of you ever experienced the same ?
Any advice ?


thank you,
liviu.