Thank you for the clarifications. I will pay attention to this in the lab :)
I took a look to what books say about explicit-paths and found this: "In the explicit way, you must specify every router that the TE tunnel must be routed on, up to and including the tail end router. You can either specify the TE router ID or the link IP address of the intermediate routers". So this means we can use loopacks or next-hops. Also another interesting thing is that in Interarea MPLS TE, we just need to specify the ABR's in the explicit path, nothing else. We have summarized all these options in this scenario: R1---[Area 12]---R2---[Area 0]---R3---[Area 34]---R4 ! ip explicit-path name R1-R2-R3-R4-loopbacks enable next-address loose 2.2.2.2 next-address loose 3.3.3.3 next-address loose 4.4.4.4 ! ip explicit-path name R1-R2-R3-R4-loopbacks-2 enable next-address loose 2.2.2.2 next-address loose 3.3.3.3 ! ip explicit-path name R1-R2-R3-R4-nexthop enable next-address 12.12.12.2 next-address loose 23.23.23.3 next-address loose 34.34.34.4 next-address loose 4.4.4.4 ! ip explicit-path name R1-R2-R3-R4-nexthop-2 enable next-address 12.12.12.2 next-address loose 23.23.23.3 next-address loose 34.34.34.4 ! The tunnel from R1 to R4 will come up with any of these explicit-paths. Regards, Antonio Soares, CCIE #18473 (R&S) [email protected] -----Original Message----- From: Jared Scrivener [mailto:[email protected]] Sent: terça-feira, 9 de Junho de 2009 18:01 To: Antonio Soares Cc: [email protected] Subject: Re: VOL2 - Section 1 I normally use loopbacks as a personal preference for each hop, but they need to be advertised into OSPF for that method to work and they aren't always. In the lab be very careful about strict vs loose mode - they serve different purposes. Strict says "take this specific path", loose says "go via this device". The lab will indicate which it needs. With Loose Mode remember that your OSPF (or ISIS) topology will dictate the best path to the next hop based on the CSPF algorithm. Strict Mode essentially source routes the tunnel. On 6/9/09 12:49 PM, "Antonio Soares" <[email protected]> wrote: > But do you see any problem if we only use loose mode ? I know it > works but should we be carefull with this in the lab ? > > And can you please comment the next-hop vs loopback address usage in > the explicit-paths ? > > > Regards, > > Antonio Soares, CCIE #18473 (R&S) > [email protected] > > -----Original Message----- > From: Jared Scrivener [mailto:[email protected]] > Sent: terça-feira, 9 de Junho de 2009 17:17 > To: Antonio Soares > Cc: [email protected] > Subject: Re: VOL2 - Section 1 > > Strict-mode explicit next hop can only be used up to the ABR as we > only have full knowledge of our MPLS TE area not other areas or AS's. > Loose-mode can be used to indicate a device in another area as we > aren't concerned with how we get there, just that we do. > > > On 6/8/09 9:36 PM, "Antonio Soares" <[email protected]> wrote: > >> Hello Jared, >> >> Can you please comment my posts about VOL2-Section 1 ? Or pointing me >> to the place where i can find information about it ? >> >> This lab was fantastic. But i want to clarify some issues i faced >> before moving on. I hope the next 4 are so challenging as this one >> :) >> >> >> Thanks. >> >> Regards, >> >> Antonio Soares, CCIE #18473 (R&S) >> [email protected] >> >> > > Cheers, > > Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP Sr. Technical > Instructor - IPexpert, Inc. > URL: http://www.IPexpert.com > Telephone: +1.810.326.1444 > Fax: +1.810.454.0130 > Mailto: [email protected] > > > Cheers, Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP Sr. Technical Instructor - IPexpert, Inc. URL: http://www.IPexpert.com Telephone: +1.810.326.1444 Fax: +1.810.454.0130 Mailto: [email protected]
