Hi Acee, Yes, a simple way to prevent this from happening is to configure a full mesh of virtual links between all ABRs in the transit area. And this makes IP FRR works well too.
Thanks, Kui -----Original Message----- From: Acee Lindem [mailto:[EMAIL PROTECTED] Sent: Monday, April 30, 2007 8:28 PM To: 章魁 Cc: 'Anton Smirnov'; 'OSPF List'; 'Jin Wang' Subject: Re: [OSPF] Doubt for virtual link cost ? Hi Kui, Yes - there could be an ABR for the transit area that takes a "shortcut" across the transit area for a non-virtual link path. Other routers in the backbone will not know about this path and may take other paths. However, this is not a problem since there is no possibility of a routing loop. Additionally, the situation can easily be remedied by configuring a virtual link between the transit area routers across the "shortcut" path. Thanks, Acee On Apr 30, 2007, at 2:48 AM, 章魁 wrote: > Hi Acee, > I guess Jin is asking that a non-optimal path might be chosen when > other > routers in backbone area can't check the transit area's summary lsa to > update the intra-area route. This should be a drawback of virtual > link, I > think. > > Kui > -----Original Message----- > From: Acee Lindem [mailto:[EMAIL PROTECTED] > Sent: Monday, April 30, 2007 4:11 AM > To: Anton Smirnov > Cc: OSPF List; Jin Wang > Subject: Re: [OSPF] Doubt for virtual link cost ? > > Hi Anton, Jin, > I guess I don't really understand the point of controversy here. I > agree with Anton. Note that if there is not an active virtual link > then the non-backbone area is not a transit area. > Thanks, > Acee > On Apr 29, 2007, at 8:23 AM, Anton Smirnov wrote: > >> Jin, >> right. In network design where such scenario is possible you >> always >> can create VL between this ABR and ABR providing best path via >> transit >> area. This will make the best path 'visible' to other routers in >> backbone. >> >> Anton >> >> >> Jin Wang wrote: >>> >>> Thanks for anton's response. >>> But if so,only the traffic going through this ABR(determined >>> before 16.3 >>> calculating result) is forwarded by the new optimal path.For those >>> other >>> traffic not forwarded via this ABR(determined by 16.1 & 16.2) in the >>> backbone will not consider the new path(via ABR) even path is >>> shorter.right? >>> >>> >>> Best regards, >>> >>> Wangjin >>> Accton Technology China Company Ltd. >>> Shanghai R&D Center >>> TEL:+86-021-64859922*6227 >>> E-mail:[EMAIL PROTECTED] >>> Web Site:www.accton.com.cn >>> >> >> >> _______________________________________________ >> OSPF mailing list >> [email protected] >> https://www1.ietf.org/mailman/listinfo/ospf > > > _______________________________________________ > OSPF mailing list > [email protected] > https://www1.ietf.org/mailman/listinfo/ospf > > _______________________________________________ OSPF mailing list [email protected] https://www1.ietf.org/mailman/listinfo/ospf
