From: jonatale@xxxxxxxxxxxxx
Date: Fri Aug 17 2001 - 04:01:21 GMT-3
i think demand circuit is a diff net type than p2p and than virtLink, demand
ckts came out in a later rfc
need to check the ospf database router LSA - should show the net type, or find
the rfc
(kind of a guess)
John.K.Feuerherd@WellsFargo.COM wrote:
> Sanjay,
> An OSPF Virtual link is considered a point-to-point circuit but it
> is run as a demand circuit. This means that once the adjacency is
> established the OSPF hellos and LSA refresh functions are suppressed. I
> guess OSPF treats Virtual links as a bandwidth sensitive link.....
>
> You can see this happen if you set it up in a lab and before you do the
> "area X virtual-link x.x.x.x" command do a "debug OSPF adj" and you will see
> the hellos suppressed after the link reaches a FULL state.
>
> Thanks,
> JF
>
> -----Original Message-----
> From: Chuck Larrieu [mailto:chuck@cl.cncdsl.com]
> Sent: Thursday, August 16, 2001 6:57 PM
> To: sanjay; ccielab@groupstudy.com
> Subject: RE: OSPF Virtual Link question
>
> I'll let you look up RFC 1793 and report back to us what you discover. ;->
>
> Good Reading!
>
> Chuck
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> sanjay
> Sent: Thursday, August 16, 2001 5:31 PM
> To: Chuck Larrieu; ccielab@groupstudy.com
> Subject: Re: OSPF Virtual Link question
>
> Look at the info on the bottom. I have 2 routers connected back to back via
> serial inter. R1 has an interface in Area 0 and the serial interface in Area
> 2. On R2 a loopback interface is in Area 4 and the serial link is in Area 2.
> I have configured the Loopback interface with "ip ospf network
> point-to-point" .
>
> r3#sh ip ospf virtual-links
>
> Virtual Link OSPF_VL0 to router 170.100.4.1 is up
> Run as demand circuit
> DoNotAge LSA allowed.
> Transit area 2, via interface Serial2/0:1, Cost of using 74
> Transmit Delay is 1 sec, State POINT_TO_POINT,
> Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
> Hello due in 00:00:07
> Adjacency State FULL (Hello suppressed)
>
> r3#
>
> ----- Original Message -----
> From: "Chuck Larrieu" <chuck@cl.cncdsl.com>
> To: "sanjay" <ccienxtyear@hotmail.com>; <ccielab@groupstudy.com>
> Sent: Thursday, August 16, 2001 4:56 PM
> Subject: RE: OSPF Virtual Link question
>
> > it operates as a point to point link. why? because the RFC says so. :->
> >
> > from RFC 2328:
> >
> > The virtual link is treated as if it were an unnumbered point-to-
> > point network belonging to the backbone and joining the two area
> > border routers. An attempt is made to establish an adjacency over
> > the virtual link. When this adjacency is established, the virtual
> > link will be included in backbone router-LSAs, and OSPF packets
> > pertaining to the backbone area will flow over the adjacency. Such
> > an adjacency has been referred to in this document as a "virtual
> > adjacency".
> >
> > the cost of the link is the sum of the costs of the links across the
> transit
> > area.
> > for the real low down check out ftp://ftp.isi.edu/in-notes/rfc2328.txt
> >
> > HTH
> >
> > Chuck
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > sanjay
> > Sent: Thursday, August 16, 2001 4:41 PM
> > To: ccielab@groupstudy.com
> > Subject: OSPF Virtual Link question
> >
> >
> > Does the virtual link run as a demand circuit and why ?
> >
> > -sanjay
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