[j-nsp] Strange IS-IS Problem

[Chuck Anderson]

On Mon, Mar 08, 2010 at 12:51:33PM -0500, Eric Van Tol wrote:
> Sorry for responding to my own post here.  Another helpful tip came 
> in to use 'point-to-point' in the ISIS config, which had been 
> brought up before but never tried.  It appears that this actually 
> works.  The person who suggested it also mentioned having similar 
> problems on Force10 switches.  Unfortunately, the point-to-point 
> solution won't work for me in the long term :-(

Ah.  I wonder if that is because the IS-IS Hello PDUs are being sent 
as Ethernet Multicast frames.  L1 LAN Hellos, L2 LAN Hellos, and P2P 
Hellos use different destination Ethernet Multicast addresses that the 
EX2500 might not be flooding like it should.  Or could it be that you 
have a Level or Area mismatch (I guess not because you haven't turned 
off any Levels, and Level 2 adjacencies don't require matching Area 
IDs)?

What does "monitor traffic interface xe-1/2/0 no-resolve 
layer2-headers extensive" show?

When I tested with and without point-to-point, I see the following:

normal ethernet, Level 1 LAN Hello:

0:90:69:bc:2c:7e > 1:80:c2:0:0:14, ethertype 802.1Q (0x8100), length 
69: vlan 999, p 6, LLC, dsap OSI (0xfe) Individual, ssap OSI (0xfe) 
Command, ctrl 0x03: OSI NLPID IS-IS (0x83): length 48
	L1 Lan IIH, hlen: 27, v: 1, pdu-v: 1, sys-id-len: 6 (0), max-area: 3 (0)

normal ethernet, Level 2 LAN Hello:

0:90:69:bc:2c:7e > 1:80:c2:0:0:15, ethertype 802.1Q (0x8100), length 
75: vlan 999, p 6, LLC, dsap OSI (0xfe) Individual, ssap OSI (0xfe) 
Command, ctrl 0x03: OSI NLPID IS-IS (0x83): length 54
	L2 Lan IIH, hlen: 27, v: 1, pdu-v: 1, sys-id-len: 6 (0), max-area: 3 (0)

point-to-point, P2P Hello:

0:90:69:bc:2c:7e > 9:0:2b:0:0:5, ethertype 802.1Q (0x8100), length 
69: vlan 999, p 6, LLC, dsap OSI (0xfe) Individual, ssap OSI (0xfe) 
Command, ctrl 0x03: OSI NLPID IS-IS (0x83): length 48
	p2p IIH, hlen: 20, v: 1, pdu-v: 1, sys-id-len: 6 (0), max-area: 3 (0)