Re: VPN multicast RPF lookup failure

From: Mike (mhhchan@gmail.com)
Date: Mon Mar 30 2009 - 05:57:36 ART


Hi Roman,

172.9.48.4 is the source and 172.9.11.1 is the receiver and RP.
R8 and R6 both of them are PE router. MSDP is running between them because
R8 and R6 are in difference BGP AS.
MSDP is fine and up.

I have check the RFP for the source, it fail on the other side PE (R6).
However, there is route in the unicast table.
If there is route in the unicast routing table, should the RPF pass?

R6#show ip rpf vrf ABC 172.9.48.4
RPF information for ? (172.9.48.4) failed, no route exists
R6#

R6#show ip route vrf ABC 172.9.48.4
Routing entry for 172.9.48.0/24
  Known via "bgp 267", distance 200, metric 0
  Tag 89, type internal
  Redistributing via ospf 200
  Advertised by ospf 200 subnets
  Last update from 10.10.7.7 01:33:53 ago
  Routing Descriptor Blocks:
  * 10.10.7.7 (Default-IP-Routing-Table), from 10.10.2.2, 01:33:53 ago
      Route metric is 0, traffic share count is 1
      AS Hops 1
      Route tag 89
      MPLS Required

R6#

For the PE-CE interfaces, I am running sparse mode in between PE-CE
interfaces.
The RP is static RP in both PE and CE

R8#show ip pim vrf ABC rp mapping
PIM Group-to-RP Mappings

Group(s): 224.0.0.0/4, Static
    RP: 172.9.11.1 (?)
R8#

I have checked the MDT on both PE, the interface is up, and I can see there
are entries in the mroute table for group 239.1.1.1 for both PE

R8#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report, Z - Multicast
Tunnel
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.1.1.1), 01:35:53/stopped, RP 10.10.8.8, flags: SJCZ
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    MVRF ABC, Forward/Sparse, 01:35:53/00:00:22

(10.10.6.6, 239.1.1.1), 01:35:10/00:02:42, flags: MTZ
  Incoming interface: Serial2/0, RPF nbr 9.9.28.2
  Outgoing interface list:
    MVRF ABC, Forward/Sparse, 01:35:10/00:01:04

(10.10.8.8, 239.1.1.1), 01:35:53/00:03:12, flags: TAZ
  Incoming interface: Loopback0, RPF nbr 0.0.0.0
  Outgoing interface list:
    Serial2/0, Forward/Sparse, 00:43:59/00:02:50

(*, 224.0.1.40), 01:38:40/00:03:07, RP 10.10.8.8, flags: SJCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:

R8#

R6#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report, Z - Multicast
Tunnel
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.1.1.1), 01:37:22/stopped, RP 10.10.6.6, flags: SJCZ
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    MVRF ABC, Forward/Sparse, 01:37:22/00:01:49

(10.10.6.6, 239.1.1.1), 01:37:22/00:03:20, flags: TAZ
  Incoming interface: Loopback0, RPF nbr 0.0.0.0
  Outgoing interface list:
    Ethernet1/1.26, Forward/Sparse, 00:44:28/00:03:22

(10.10.8.8, 239.1.1.1), 01:36:22/00:02:40, flags: MTZ
  Incoming interface: Ethernet1/1.26, RPF nbr 9.9.26.2
  Outgoing interface list:
    MVRF ABC, Forward/Sparse, 01:36:22/00:02:49

(*, 239.255.7.7), 01:37:08/00:03:20, RP 10.10.6.6, flags: S
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Ethernet1/1.26, Forward/Sparse, 01:37:08/00:03:20

(*, 224.0.1.40), 01:39:12/00:02:53, RP 0.0.0.0, flags: DCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Loopback0, Forward/Sparse, 01:39:11/00:02:53
    Ethernet1/1.26, Forward/Sparse, 01:37:15/00:02:01

R6#

But I checked the MDT updates from the bgp, there is nothing.
Does it mean MDT is not working?

R8#show ip pim mdt bgp
Peer (Route Distinguisher + IPv4) Next Hop
R8#
R8#

R8#show ip pim mdt
  MDT Group Interface Source VRF
* 239.1.1.1 Tunnel0 Loopback0 ABC
R8#
R8#

R8#show ip pim mdt bgp
Peer (Route Distinguisher + IPv4) Next Hop
R8#

R6#show ip pim mdt
  MDT Group Interface Source VRF
* 239.1.1.1 Tunnel0 Loopback0 ABC
R6#

R6#show ip pim mdt bgp
Peer (Route Distinguisher + IPv4) Next Hop
R6#

On Mon, Mar 30, 2009 at 2:50 AM, Roman Rodichev <roman@iementor.com> wrote:

> Why are you checking RPF for the destination 172.9.11.1, aren't you
> interested in RPF check for the source 172.9.48.4? If 172.9.11.1 is a
> multicast receiver, you don't really care about RPF checks for that IP
> address, as you'll never see that IP anywhere in the multicast packet.
>
> Something else could be wrong in your case. Which PIM mode have you
> configured on your customer (PE-CE) interfaces? If sparse mode, is RP
> known?
> "show ip pim vrf ABC rp mapping"? Do you have any static mroutes configured
> in vrf ABC? Is MDT running? "show ip pim mdt bgp"
>
>
> Roman Rodichev
> 5xCCIE #7927 (R&S, Security, Voice, Storage, Service Provider)
> Instructor, Content Developer
> ieMentor Corporation http://www.iementor.com
> Y!M: roman7927
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Mike
> Sent: Sunday, March 29, 2009 10:39 AM
> To: ccielab@groupstudy.com
> Subject: VPN multicast RPF lookup failure
>
> Hi,
>
> I have a RPF lookup issue in my VPN multicast configuration.
> From the vrf table, there is a route for the destination 172.9.11.1. Just
> don't know why it fail the RPF lookup.
>
> R8#
> 02:39:35: IP(1): s=172.9.48.4 (Ethernet1/0.48) d=224.1.1.1 id=186, ttl=254,
> prot=1, len=114(100), RPF lookup failed for source or RP
>
> R8#show ip rpf vrf ABC 172.9.11.1
> RPF information for ? (172.9.11.1) failed, no route exists
> R8#
>
> R8#show ip route vrf ABC
>
> Routing Table: ABC
> Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
> ia - IS-IS inter area, * - candidate default, U - per-user static
> route
> o - ODR, P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 172.9.0.0/24 is subnetted, 3 subnets
> C 172.9.48.0 is directly connected, Ethernet1/0.48
> B 172.9.11.0 [20/0] via 10.10.7.7, 01:12:05
> B 172.9.16.0 [20/0] via 10.10.7.7, 01:12:05
> 10.0.0.0/32 is subnetted, 1 subnets
> R 10.10.4.4 [120/1] via 172.9.48.4, 00:00:08, Ethernet1/0.48
> R8#
>
> R8#show ip route vrf ABC 172.9.11.1
> Routing entry for 172.9.11.0/24
> Known via "bgp 89", distance 20, metric 0
> Tag 267, type external
> Redistributing via rip
> Advertised by rip metric 1
> Last update from 10.10.7.7 01:11:52 ago
> Routing Descriptor Blocks:
> * 10.10.7.7 (Default-IP-Routing-Table), from 10.10.7.7, 01:11:52 ago
> Route metric is 0, traffic share count is 1
> AS Hops 1
> Route tag 267
> MPLS Required
>
>
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