From: Jonathan V Hays (jhays@jtan.com)
Date: Thu Nov 20 2003 - 18:52:18 GMT-3
Ken,
1. Be careful of your NET statements.
In Cisco IOS you can get away with a 1-byte area ID, which in this case
is 49. But most people would use 49 for the AFI (Authority and Format
Identifier), as in 49.aaaa.xxxx.xxxx.xxxx.00, where
49 = AFI
aaaa = area ID
xxxx.xxxx.xxxx = system ID
00 = selector byte.
In this case, the IOS decided you meant area 49 and both routers were
assigned to area 49. Is this really what you had in mind?
2. Page 50 of Abe Martey's "IS-IS Network Design Solutions" states that
"the default hello interval is 10 seconds for ordinary routers and 3.3
seconds for the designated intermediate system on a multicaccess link."
Take a closer look at your debug and you will see that one side is
sending hellos every 4 or 5 seconds but the other side sends them every
12 to 13 seconds.
On the same page, it also says "The hello interval is jittered, up to
about 25 percent to reduce the likeliness of synchronized IIH
transmission over the network."
From the above information, I would guess that the DIS (designated
intermediate system) ignores the "isis hello-interval" command and sends
at 3.3 seconds (plus or minus 25% jitter) regardless. The other side is
close to 15 seconds, if you account for jitter.
I am no IS-IS guru. This is just my conclusion from a little research.
Jonathan
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Ken.Farrington@barclayscapital.com
Sent: Thursday, November 20, 2003 3:07 PM
To: ccielab@groupstudy.com
Subject: ISIS Hello Packet Problem
Guys, have rtr1---------rtr2
rtr1 is sending isis hello packets every 5 seconds even though I set the
isis hello-interval to 15 seconds. Router 2 seems to be working
correctly.
I have tried this on two different platforms now, 4700 running
enterprise
on code 12.2x and 2500s runnign 12.0xx
Anyone have any ideas on this please?
Many thx
****Router1*****
!
interface Ethernet0
ip address 200.200.1.1 255.255.255.0
ip router isis
no ip route-cache
no ip mroute-cache
media-type 10BaseT
isis circuit-type level-1
isis hello-interval 15
!
!
router isis
net 49.1111.1111.1111.00
!
****Router2*****
!
interface FastEthernet0
ip address 200.200.1.2 255.255.255.0
ip router isis
half-duplex
fair-queue
isis circuit-type level-1
isis hello-interval 15
!
!
router isis
net 49.2222.2222.2222.00
!
TEST1#
01:05:46: ISIS-Adj: Rec L1 IIH from 0000.0c5c.b719 (Ethernet0), cir type
L1,
cir id 1111.1111.1111.01, length 1497
01:05:50: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:05:54: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:05:59: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:06:00: ISIS-Adj: Rec L1 IIH from 0000.0c5c.b719 (Ethernet0), cir type
L1,
cir id 1111.1111.1111.01, length 1497
01:06:04: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:06:09: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:06:13: ISIS-Adj: Sending L1 LAN IIH on Ethernet0, length 1497
01:06:13: ISIS-Adj: Rec L1 IIH from 0000.0c5c.b719 (Ethernet0), cir type
L1,
cir id 1111.1111.1111.01, length 1497undeb all
All possible debugging has been turned off
TEST1#
TEST2#
01:04:26: ISIS-Adj: Sending L1 LAN IIH on FastEthernet0, length 1497
01:04:26: ISIS-Adj: Rec L1 IIH from 0060.3e10.ac20 (FastEthernet0), cir
type
L1, cir id 1111.1111.1111.01, length 1497
01:04:31: ISIS-Adj: Rec L1 IIH from 0060.3e10.ac20 (FastEthernet0), cir
type
L1, cir id 1111.1111.1111.01, length 1497
01:04:35: ISIS-Adj: Rec L1 IIH from 0060.3e10.ac20 (FastEthernet0), cir
type
L1, cir id 1111.1111.1111.01, length 1497
01:04:38: ISIS-Adj: Sending L1 LAN IIH on FastEthernet0, length 1497
01:04:39: ISIS-Adj: Rec L1 IIH from 0060.3e10.ac20 (FastEthernet0), cir
type
L1, cir id 1111.1111.1111.01, length 1497
01:04:43: ISIS-Adj: Rec L1 IIH from 0060.3e10.ac20 (FastEthernet0), cir
type
L1, cir id 1111.1111.1111.01, length 1497
01:04:48: ISIS-Adj: Rec L1 IIH from 0060.3e10.ac20 (FastEthernet0), cir
type
L1, cir id 1111.1111.1111.01, length 1497
01:04:50: ISIS-Adj: Sending L1 LAN IIH on FastEthernet0, length 1497
TEST2#undeb all
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