From: Brian McGahan (brian@cyscoexpert.com)
Date: Tue Mar 18 2003 - 03:30:58 GMT-3
Yes GRE would work, however the preferred method is just to use multiple
point-to-point subnets.
Brian McGahan, CCIE #8593
Director of Design and Implementation
brian@cyscoexpert.com
CyscoExpert Corporation
Internetwork Consulting & Training
Toll Free: 866-CyscoXP
Outside US: 847.674.3392
Fax: 847.674.2625
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Sanfilippo, Ted
> Sent: Monday, March 17, 2003 7:05 PM
> To: 'stefan vogt'; Brian McGahan; ccielab@groupstudy.com
> Subject: RE: RE: ISIS and designated IS (DIS)
>
> Just to add to the question, if IS-IS cannot work with hub and spoke.
Is
> it
> prefered to do a tunnel for all hub and spoke sites, or will this not
work
> also?
>
> Ted
>
> -----Original Message-----
> From: stefan vogt [mailto:stefan-uwe_vogt@web.de]
> Sent: Monday, March 17, 2003 3:53 PM
> To: Brian McGahan; ccielab@groupstudy.com
> Subject: Re: RE: ISIS and designated IS (DIS)
>
>
> Hello Brian,
>
> Many thanks for your answers. But your answer rises a new question for
me:
>
> >As for Frame-Relay, IS-IS does not run over hub and spoke,
> > therefore DIS election is not really an issue.
>
> Why does IS-IS not run over hub and spoke?
>
> -Stefan
>
>
>
> "Brian McGahan" <brian@cyscoexpert.com> schrieb am 17.03.03 20:53:23:
> >
> > Stefan,
> >
> > The DIS in IS-IS is like the DR/BDR in OSPF. However, the DIS
> > election is preemptive, and there is no backup DIS. There is one
DIS
> > per broadcast segment per level.
> >
> > To determine which router is the DIS, 'show clns is-neighbors'.
> > On a broadcast segment, the Circuit ID is the system ID of the DIS.
In
> > addition to this, you can see the Pseudonode LSP in the ISIS
database.
> > In the following example, there are two routers on a broadcast
segment,
> > R1 & R6. DIS election is on a per level basis. Since R6 has a
level-1
> > priority of 60, R1 is elected DIS for level-1 (R1 has default of
64).
> > However, since R6 has a level-2 priority of 70, it is elected DIS
for
> > level-2.
> >
> > R6#sh run int e0/0
> > Building configuration...
> >
> > Current configuration : 142 bytes
> > !
> > interface Ethernet0/0
> > ip address 16.0.0.6 255.0.0.0
> > ip router isis
> > half-duplex
> > isis priority 60 level-1
> > isis priority 70 level-2
> > end
> >
> > R6#sh isis databas
> >
> > IS-IS Level-1 Link State Database:
> > LSPID LSP Seq Num LSP Checksum LSP Holdtime
> > ATT/P/OL
> > R6.00-00 * 0x00000002 0xCA67 1083
0/0/0
> > R1.00-00 0x00000004 0x9670 1054
0/0/0
> > R1.01-00 0x00000001 0xF2C9 1077
0/0/0
> > IS-IS Level-2 Link State Database:
> > LSPID LSP Seq Num LSP Checksum LSP Holdtime
> > ATT/P/OL
> > R6.00-00 * 0x00000001 0xF075 1078
0/0/0
> > R6.01-00 * 0x00000001 0x4F29 1079
0/0/0
> > R1.00-00 0x00000006 0xB681 1081
0/0/0
> > R6#
> >
> > For the level-1 link state database, you can see that R1
> > generates is own LSP as well as an LSP for the pseudonode, denoted
by
> > the R1.01-00 LSPID. For level-2, R6 is the DIS, hence the LSPID of
> > R6.00-00 and R6.01-00.
> >
> > As for Frame-Relay, IS-IS does not run over hub and spoke,
> > therefore DIS election is not really an issue.
> >
> > For more info on DIS election:
> >
> >
http://www.cisco.com/en/US/tech/tk472/tk474/technologies_tech_note09186a
> > 0080094b42.shtml
> >
> >
> > HTH
> >
> > Brian McGahan, CCIE #8593
> > Director of Design and Implementation
> > brian@cyscoexpert.com
> >
> > CyscoExpert Corporation
> > Internetwork Consulting & Training
> > Toll Free: 866.CyscoXP
> > Fax: 847.674.2625
> >
> >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
Behalf
> > Of
> > > stefan vogt
> > > Sent: Monday, March 17, 2003 9:20 AM
> > > To: ccielab@groupstudy.com
> > > Subject: ISIS and designated IS (DIS)
> > >
> > > Hi group,
> > >
> > > I have some questions regarding ISIS and designated IS (DIS).
> > >
> > > 1) I know that I can change the isis priority per interface. Is
the
> > DIS
> > > eleceted per LAN segment or per area?
> > > 2) Is a DIS elected/required also for FR point-to-multipoint
> > connections?
> > > Which implications does this have to hub-and-spoke type
> > configurations?
> > > 3) What's the easiest way to figure out which router is elected as
> > DIS?
> > >
> > > Any input or link is appreciated.
> > >
> > > -Stefan
> > >
> >
This archive was generated by hypermail 2.1.4 : Sat Apr 05 2003 - 08:51:41 GMT-3