PIM proxy vector on XR

[anazarenko]

Dear All,

I have IOS based PE R1, R3 is another PE side in different autonomous system:

R1#sh bgp ipv4 mdt all
BGP table version is 18, local router ID is 10.10.10.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 10:1 (default for vrf A)
*> 10.10.10.1/32    0.0.0.0                                0 ?
Route Distinguisher: 1010:1
*>i10.10.10.3/32    10.10.10.9                    100      0 1010 ?

This information gets passed to PIM process

*Jul  3 01:49:11.820: PIM(0): Insert (10.10.10.3,232.1.1.1) join in nbr 10.10.19.9's queue
*Jul  3 01:49:11.820: PIM(0): Building Join/Prune packet for nbr 10.10.19.9
*Jul  3 01:49:11.820: PIM(0):  Adding v2 (10.10.10.3/32, 232.1.1.1), S-bit Join MDT proxy 1010:1/10.10.10.9
*Jul  3 01:49:11.820: PIM(0): Send v2 join/prune to 10.10.19.9 (FastEthernet0/0.19)

Pim process is configured with "ip multicast vrf A rpf proxy rd vector"

R1 is peering with R9, which is IOS XR ASBR:

When R9 receives my (S,G) join without rpf-vector command under pim router I have:

RP/0/0/CPU0:Jul  3 12:29:59.792 : pim[328]: [7] VRF : default J/P recvieved when proxy is disabled to 10.10.10.3
That's logical. The i enable rpf-vector and see the following in its debug:

RP/0/0/CPU0:Jul  3 12:47:41.857 : pim[328]: [7] VRF : default  Received J/P on Gi0/4/0/0 from 10.10.19.1 target: 10.10.19.9 (to us)
RP/0/0/CPU0:Jul  3 12:47:41.857 : pim[328]: [7] VRF : default Hash not required from 224.0.0.0/10.10.10.9
RP/0/0/CPU0:Jul  3 12:47:41.857 : pim[328]: [7] VRF : default Best Matching grange (232.0.0.0,0.0.0.0) for group 232.1.1.1
RP/0/0/CPU0:Jul  3 12:47:41.858 : pim[328]: [7]  J/P group 232.1.1.1 found grange in vrf default
RP/0/0/CPU0:Jul  3 12:47:41.858 : pim[328]: [7] VRF : default J/P with unknown proxy type 2 forwarding...
RP/0/0/CPU0:Jul   3 12:47:41.858 : pim[328]: [7] VRF : default J/P entry: Join root:  10.10.10.3 proxy 0.0.0.0 group: 232.1.1.1 target: 10.10.19.9 flags:  S  on interface Gi0/4/0/0 sender 10.10.19.1

I gets finally dropped. ps: I am using 3.6.3 xr.

RP/0/0/CPU0:ios#sh pim bgp-safi
grp 232.1.1.1   src 10.10.10.1  rd 10:1         nexthop 10.10.10.1
grp 232.1.1.1   src 10.10.10.3  rd 1010:1       nexthop 10.10.29.2

RP/0/0/CPU0:ios#sh mrib ipv4  route
IP Multicast Routing Information Base
Entry flags: L - Domain-Local Source, E - External Source to the Domain,
    C - Directly-Connected Check, S - Signal, IA - Inherit Accept,
    IF - Inherit From, D - Drop, MA - MDT Address, ME - MDT Encap,
    MD - MDT Decap, MT - MDT Threshold Crossed, MH - MDT interface handle
    CD - Conditional Decap
Interface flags: F - Forward, A - Accept, IC - Internal Copy,
    NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
    II - Internal Interest, ID - Internal Disinterest, LI - Local Interest,
    LD - Local Disinterest, DI - Decapsulation Interface
    EI - Encapsulation Interface, MI - MDT Interface

(*,224.0.0.0/4) RPF nbr: 10.10.10.9 Flags: L C
  Up: 04:38:24
  Outgoing Interface List
    Decapstunnel0 Flags: NS DI, Up: 04:38:24

(*,224.0.0.0/24) Flags: D
  Up: 04:39:48

(*,224.0.1.39) Flags: S
  Up: 04:39:48

(*,224.0.1.40) Flags: S
  Up: 04:39:48
  Outgoing Interface List
    Loopback0 Flags: II LI, Up: 04:39:48

(*,232.0.0.0/8) Flags: D
  Up: 04:39:48

(10.10.10.1,232.1.1.1) RPF nbr: 0.0.0.0 Flags:
  Up: 00:18:53

(10.10.10.3,232.1.1.1) RPF nbr: 0.0.0.0 Flags:
  Up: 00:18:53

Maybe i am mising something, there's IOS-based ASBR in other AS and it behaves normally as expected.

[Luc De Ghein · Accepted solution]

Hi,

You used RPF Vector with RD on the IOS router.

IOS-XR only understands RPF Vector without RD.

IOS-XR only has the command rpf-vector.

So it seems that this is the reason that we see the following debug line:

RP/0/0/CPU0:Jul  3 12:47:41.858 : pim[328]: [7] VRF : default J/P with unknown proxy type 2 forwarding...

Thanks,

Luc

[anazarenko]

Dear Luc,

Can you plz elaborate little bit. When I try to use RPF Vector without RD on Cisco IOS (

ip multicast vrf A rpf proxy  vector)

, it doesn't trigger SSM join request.  I don't have RPF info on PE routers for the peer MDT endpoint either in RIB or in MRIB and RD Vector works well for me. Can you also provide some source where I can read about RPF Vector (without RD) usage.

[Luc De Ghein · Accepted solution]

Hi,

To use RPF vector without VRF/RD -in IOS- you need to configure: "ip multicast rpf proxy vector".

This is used in scenarios without RD, hence without VRF.

An example is a network with BGP speakers on the edge and the core routers do not run BGP.

This is an MPLS network (not MPLS VPN network), where you have the edge routers running

BGP and the core routers do not.

This is described here:

RFC 5496   The Reverse Path Forwarding (RPF) Vector TLV

section 3.  Use of the RPF Vector TLV

But, if you are trying to implment MVPN in an Inter-as option B scenario,
then you must use the command with the RD option.

Thanks,

Luc