RE: PIM NBMA Mode

From: Alex Steer (alex.steer@eison.co.uk)
Date: Sun Nov 11 2007 - 07:22:14 ART


Hi Gops,

It might be, it might not. Could you send a full copy of your show ip
mroute on all of the routers please (specifically the S,G entry)?

Nbma is primarily to stop a prune from one of the spokes sent to r5 from
pruning the other neighbors (default behaviour without nbma mode). The
other neighbors don't see the prune due to the Non-broadcast nature of
the interface and so don't prune override it. Pim nbma causes pim to
store network-hop information for that interface, that doesn't mean it
can unicast the packet to that 1 neighbor though, merely means it wont
prune the interface when it receives a prune from one of the neighbors.
It would be good for my own study to see the output.

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gupta, Gopal (NWCC)
Sent: 11 November 2007 09:56
To: Cisco certification
Subject: PIM NBMA Mode

Hi Folks,

There is issue with pim NBMA mode.

R5 is the hub Router and sending traffic to group 232.2.2.2, The problem
here is that despite of putting ip pim NBMA command on R5 Serial
interface, i am getting three replies; means R5 is still sending traffic
to all DLCIs configured under R5 serial interface.

R5#ping 232.2.2.2

Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 232.2.2.2, timeout is 2 seconds:

Reply to request 0 from 155.1.67.6, 324 ms
Reply to request 0 from 155.1.67.6, 728 ms
Reply to request 0 from 155.1.67.6, 504 ms

Debugs:-

*Mar 1 11:26:16.277: Serial1/0(o): dlci 504(0x7C81), pkt type
0x800(IP), datagramsize 444
*Mar 1 11:26:16.277: Serial1/0(o): dlci 501(0x7C51), pkt type
0x800(IP), datagramsize 444
*Mar 1 11:26:16.289: Serial1/0(o): dlci 503(0x7C71), pkt type
0x800(IP), datagramsize 444

These packets are packets for 232.2.2.2 address.

R5#sh ip mr 232.2.2.2

IP Multicast Routing Table

(*, 232.2.2.2), 00:18:05/00:03:14, RP 150.1.5.5, flags: S
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Serial1/0, 155.1.0.3, Forward/Sparse, 00:17:43/00:03:14

Config :--

interface Serial1/0
 ip address 155.1.0.5 255.255.255.0
 ip pim nbma-mode
 ip pim sparse-mode
 encapsulation frame-relay
 no ip route-cache cef
 no ip route-cache
 serial restart-delay 0
 no dce-terminal-timing-enable
 frame-relay map ip 155.1.0.1 501 broadcast
 frame-relay map ip 155.1.0.3 503 broadcast
 frame-relay map ip 155.1.0.4 504 broadcast
 end

Any Comments...how to overcome this, may i be i am missing something
here.

Thanks
Gops



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