From: navaid@rogers.com
Date: Mon Sep 08 2003 - 17:36:50 GMT-3
Brian, it is an excellent explanation.
It helped me a lot.
Thanks,
Navaid
>
> From: "Brian Dennis" <bdennis@internetworkexpert.com>
> Date: 2003/09/07 Sun PM 02:05:19 EDT
> To: 'SN K38U' <youshungang@hotmail.com>,
> <ccielab@groupstudy.com>
> Subject: RE: isis neighbor adj problem
>
> First off let me start by saying that there are two types of IS-IS
> hellos (IIH's), point-to-point and LAN. The IIH types used by IS-IS on
> an interface is based on the type of interface (point-to-point or
> multipoint)*. This is similar in a way to how OSPF determines the
> network type of an interface based off the type of interface being used.
> But unlike OSPF, IS-IS does not have any commands to change the default
> IIH type until IOS version 12.2(8)T.
>
> As of 12.2(8)T Cisco introduced a new IS-IS command that will allow the
> changing of the IIH type used for an interface from LAN IIH to
> point-to-point IIH but not from point-to-point to LAN. This new command,
> isis network point-to-point, can be applied to a multipoint interface
> (multipoint subinterface, physical Frame-Relay interface, Ethernet
> interface, etc).
>
> Basically one of the issues that you are seeing is that the
> point-to-point interface is sending point-to-point IIH's and physical
> interface is sending LAN IIH's. The IIH types need too of course match
> on each end for IS-IS to work properly. The second issue is that you
> need to map CLNS on the physical interface and include the broadcast
> keyword.
>
> Here is what will work by default:
> 1. point-to-point subinterface to a point-to-point subinterface
> 2. physical interface to a physical interface
> 3. multipoint subinterface to a multipoint subinterface
> 4. multipoint subinterface to a physical interface
>
> Here is what does not work by default:
> 1. point-to-point subinterface to a physical interface
> 2. point-to-point subinterface to a multipoint subinterface
>
> Here is what will work using the new IS-IS command on the 'multipoint'
> interface side:
> 1. point-to-point subinterface to a physical interface
> 1. point-to-point subinterface to a multipoint subinterface
>
> Remember that if you are going to run ISIS over Frame-Relay on a
> multipoint subinterface or a physical interface, you will need to map
> CLNS to the DLCI and include the broadcast keyword. This also applies to
> a physical BRI, physical ATM or an ATM multipoint subinterface.
>
> *Note: There are generally speaking two types of interfaces,
> point-to-point and multipoint. HDLC serial interfaces, dialer interfaces
> or Frame-Relay point-to-point subinterfaces are examples of
> point-to-point interface types. Ethernet interfaces, physical
> Frame-Relay interfaces, multipoint subinterfaces, BRI interfaces are
> generally considered multipoint in that they can have more than one
> device connected to them.
>
> Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
> bdennis@internetworkexpert.com
> Toll Free: 877-334-8987
> Direct: 775-745-6404 (Outside the US and Canada)
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> SN K38U
> Sent: Saturday, September 06, 2003 11:28 PM
> To: ccielab@groupstudy.com
> Subject: isis neighbor adj problem
>
> Hi group#,when I worked on a lab recently,I encountered a problem about
> isis neighbor adj.
> Here is my topology:
> r3-s1--(frame-relay)--s0-r4-| e0
> |
> s0
>
> below is the detailed config:
>
> r3:
> interface Serial0
> no ip address
> encapsulation frame-relay
> frame-relay lmi-type ansi
> !
> interface Serial0.1 point-to-point
> ip address 10.13.1.2 255.255.0.0
> ip router isis
> frame-relay interface-dlci 301
> !
> interface Serial1
> ip address 10.34.1.1 255.255.0.0
> ip router isis
> encapsulation frame-relay
> frame-relay interface-dlci 304
> frame-relay lmi-type ansi
> !
> router isis
> net 01.3333.3333.3333.00
>
> r4:
> interface Ethernet0
> ip address 10.4.1.1 255.255.0.0
> ip router isis
> !
> interface Serial0
> ip address 10.34.1.2 255.255.0.0
> ip router isis
> encapsulation frame-relay
> frame-relay interface-dlci 403
> frame-relay lmi-type ansi
> !
> router isis
> net 01.4444.4444.4444.00
>
> I found that r3 and r4 cannot form isis neighbors.
> When i debug the isis neighbor adj,here is the output:
> r3#debug isis adj
> IS-IS Adjacency related packets debugging is on
> r3#
> 00:03:14: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial1
> 00:03:15: ISIS-Adj: Encapsulation failed for L2 LAN IIH on Serial1
> on r4,there is the same problem.
>
> That confused me.The s0 should send serial IIH instead of LAN IIH since
> it
> is not a lan interface.Why the interface s0 does not behave normally?
> What
> cause this situation?
> Who can help out the problem? I wasted too much time on it.
> Please clarify it. Thanks a lot for any help!
>
> _________________________________________________________________
> OmSCJ@=gIOWn4s5D5gWSSJ<~O5M3!* MSN Hotmail!# http://www.hotmail.com
>
>
> _______________________________________________________________________
> You are subscribed to the GroupStudy.com CCIE R&S Discussion Group.
>
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
> _______________________________________________________________________
> You are subscribed to the GroupStudy.com CCIE R&S Discussion Group.
>
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
1
This archive was generated by hypermail 2.1.4 : Wed Oct 01 2003 - 07:24:24 GMT-3