The MPLS-OPS Archive

["M. ELK" <elkou141061@hotmail.com>]

Hi

Despite it was explained to me previously still facing some difficulty.
Consider the following :


R1-a-----R2-----R3-----R4

P1 prefix associated with R1 ,P2 with R2 ...etc .

All link with 10 as cost . "a" is the interface of R1

currently at R1 :

Prefix      Cost    Via
P2           10       a
P3           20       a
p4           30       a

Set T1 from R1 to R4 with absolute metric 1 :

Case 1 :

Prefix         Cost         Via
P2              10          a
P3              20          a
p4              1           T1

Case 2 :

Prefix      Cost    Via
P2           10       a
P3           11      T1
p4           1        T1

Is it case 1 or case 2 (mainly for P3) ??
My guess it will be case 1 to follow draft-ietf-rtgwg-igp-shortcut-00.txt, 
but what are the reason
to prefer this approach , is it to avoid any possible loop ??? If yes : 
could U pls provide an
example of topology where loop could exist .

.

Now :
Config T2 from R4 to R1 with absolute metric 1 .
R1 and R4 are config to advertise T1,T2  as link in the IGP .

at R1 :  could we expect that it is now case 2 ??? .


Brgds

_________________________________________________________________
The new MSN 8: advanced junk mail protection and 2 months FREE* 
http://join.msn.com/?page=features/junkmail

-------
The MPLS-OPS Mailing List
Subscribe/Unsubscribe:  http://www.mplsrc.com/mplsops.shtml
Archive: http://www.mplsrc.com/mpls-ops_archive.shtml