From: Prakash H Somani (pdsccie@xxxxxxxxxxxxxx)
Date: Tue Jul 16 2002 - 05:28:50 GMT-3
Hi Group,
I am working on following scenario:
R1
/ \
/ \
R5 R6
R1 Serial interface multipoint
R5 Serial interface multipoint
R6 Serial interface multipoint
PArtial FR DLCI (R5 to R1 501, R6 to R1 601, R1 to R5 105, R1 to
R6 106)
CLNS Routing enabled on all the routers.
FR MAP given for CLNS and IP
Symptoms:
1. When all interface configured for PTM, Sh CLNS neigbbour shows
UP/UP on R1-R5-R6.
2. R1 L0 route comes in R6 and vice varsa.
3. No route in R5 and even R1 does not have R5 L0 route.
4. After chaning ISIS priority on R1(Prio=100),R5(Prio=10) and
R6(Prio=10) both L0 (Both of R5 and R6) are available in R1 but R5
donot have R6 L0 and vice varsa.
I am unable to understand the phenomina...can anybody suggest
where m I wrong??? (Suggested reading)
regards...PRakash
On Mon, 15 Jul 2002 Fred Ingham wrote :
>Brian: I agree with your comments except for: " IS-IS will not
>run over a
>hub and spoke NBMA" Here is a counter example:
>
> Say that R1 is the hub with a multipoint subinterface. R2 and
>R3 are
>spokes using physical interfaces. All are in the same subnet, of
>course.
>Configure R1 as L1/L2 with net 49.0001.1111.1111.1111.00, R2 as
>L1 with net
>49.0001.2222.2222.2222.00, and R3 as L1/L2 with net
>49.0002.3333.3333.3333.00. Assuming you have CLNS maps on your
>frame cloud,
>and ip router isis on the serial interfaces, R1 will form an L1
>adjacency
>with R2 and an L2 adjacency with R3.
>
>This is part of an example that NMC-1 students configure with
>other routers
>connected off R2 and R3.
>
>Cheers, Fred
>
>----- Original Message -----
> From: "Brian McGahan" <brian@cyscoexpert.com>
>To: "'Jonathan V Hays'" <jhays@jtan.com>;
><ccielab@groupstudy.com>
>Sent: Friday, July 12, 2002 10:44 PM
>Subject: RE: ISIS - subinterface needed?
>
>
> > Johnathan,
> >
> > Actually there's a little more to it than that. With IS-IS,
> > there are only two network types, point-to-point and
>broadcast. Unlike
> > OSPF however, there is no equivalent of the 'ip ospf network'
>command.
> > The IS-IS network type is dependent on the interface type.
> >
> > Physical and multipoint NBMA interfaces are multipoint. The
> > only big difference between them is that split-horizon is
>disabled on
> > frame-relay physical interfaces. Point-to-point interfaces
>are (you
> > guessed it) point-to-point. Like OSPF, the IS-IS network type
>must
> > match for neighbors to become adjacent. Therefore, for two
>IS-IS
> > routers to become adjacent over NBMA, you need to have a
>combination of
> > physical and multipoint, or two point to point interfaces.
>This leads
> > us to two more issues that are worth mentioning.
> >
> > 1. IS-IS will not run over a hub and spoke NBMA
> > 2. IP is not the transport protocol for IS-IS
> >
> > In regards to the first issue, this means that you must have
>two
> > IP subnets if you are running a hub and spoke setup.
>Therefore you must
> > have two separate subinterfaces on the hub, or do a workaround
>such as a
> > GRE tunnel.
> >
> > Regarding the second issue, this means that physical and
> > multipoint interfaces must have layer 2 to CLNS mappings.
>For
> > frame-relay this translates to:
> >
> > frame-relay map clns [VC] broadcast
> >
> > This article should help to clarify some more.
> >
> > http://www.cisco.com/warp/public/97/isis-frint.html
> >
> > HTH,
> >
> > Brian McGahan, CCIE #8593
> > Director of Design and Implementation
> > brian@cyscoexpert.com
> >
> > CyscoExpert Corporation
> > Internetwork Consulting & Training
> > http://www.cyscoexpert.com
> > Voice: 847.674.3392
> > Fax: 847.674.2625
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
>Behalf Of
> > Jonathan V Hays
> > Sent: Friday, July 12, 2002 5:11 PM
> > To: ccielab@groupstudy.com
> > Subject: RE: ISIS - subinterface needed?
> >
> > Thanks everyone for all the informative replies!
> >
> > Jonathan
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On
>Behalf Of
> > Jonathan V Hays
> > Sent: Friday, July 12, 2002 2:17 PM
> > To: ccielab@groupstudy.com
> > Subject: ISIS - subinterface needed?
> >
> >
> > Group,
> >
> > I just had an interesting experience configuring ISIS on two
>routers.
> > One router (R1) had two serial subinterfaces, one of which
>was
> > point-to-point to another router running ISIS (R2). Now R2 was
>not
> > configured with subinterfaces, just "interface serial 0" since
>it was
> > only connected to R1 (via frame relay). I could not get ISIS
>routes to
> > appear in the routing tables of either router.
> >
> > After I changed R2 to a point-to-point subinterface the ISIS
>routes
> > popped into both routing tables.
> >
> > The question is, why is the point-to-point subinterface
>necessary on
> > both ends for ISIS to propagate routes?
> >
> > Jonathan
> >
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:36:31 GMT-3