[c-nsp] Explicit path

[Oliver Boehmer (oboehmer)]

Jeff Tantsura <mailto:jeff.tantsura at sscplus.nl> wrote on Tuesday,
February 20, 2007 10:44 AM:

> Hi Oliver,
> 
> Why do you need a floating static to null0?
> If you use explicit path without fallback to dynamic one there won't
> be any LSP to transport the video traffic via 7600C, do I miss
something?

Well, I assumed that there would be a path via the IGP to the
destination. If the destination is not advertised in the IGP, floating
static is not needed, right.

> For the VRF case - wouldn't it be easier to use "bgp next-hop" within
> VRF instead of PBR ?

Yes, this would also work, but might not be as granular (i.e. it would
affect all the traffic within the VRF)..  

	oli


> 
>> -----Original Message-----
>> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
>> bounces at puck.nether.net] On Behalf Of Oliver Boehmer (oboehmer)
>> Sent: dinsdag 20 februari 2007 7:56
>> To: Michel Renfer; cisco-nsp at puck.nether.net
>> Subject: Re: [c-nsp] Explicit path
>> 
>> Michel Renfer <> wrote on Monday, February 19, 2007 8:34 PM:
>> 
>>> Hi All
>>> 
>>> Assume the following (sample) topology with 7600/Sup720-3b, SFX7
>>> and MPLS encapsulation between all three 7600:
>>> 
>>> 
>>>  Video SRC ---2 x GE--- 7600 A =====10G====== 7600 ---2 x GE---
>>>                            Video DST \                   /
>>>                             \                 /
>>>                              \               /
>>>                             1x GE          1x GE
>>>                                \           /
>>>                                 \         /
>>>                                  \       /
>>>                                   7600 C
>>> 
>>> Video SRC sends out encapsulated MPEG2 transportstreams with a
>>> total bandwidth of approx 1.1G. Traffic between 7600 A and B
>>> can be transported inside a L3 VPN or with two EoMPLS tunnels)
>>> 
>>> How can configure, that the traffic between Video SRC and Video
>>> DST only used the path between 7600 A and B and never over C?
>>> It is clear, that in case of a failure of the 10G link, the
>>> connection between SRC and DST will be broken.
>>> 
>>> Can someone give me the right pointer(s), how this can be
>>> configured?
>> 
>> Hmm, is there a requirement to put the traffic into a L3VPN/VRF, or
>> can it be in the global table? 
>> 
>> If you can put this into the global table, just do the following
>> 1) set up a TE tunnel with an explicit-path over A-B
>> 2) statically route the destination over the tunnel and use a
>> floating static Null0 route to drop the traffic in case the tunnel
>> goes down (using PBR on 7600-A to send traffic over the tunnel
>> doesn't work until 
>> 12.2SRB)
>> 
>> If the interfaces on 7600A and B are in a VRF, you need to play
>> around with the BGP next-hop as follows:
>> 1) set up a TE tunnel as before, but enable LDP on it
>> 2) configure a new loopback interface (/32) on 7600B, and route this
>> one statically to the tunnel (with a floating Null0 route to drop
>> the traffic, as before) 3) use an inbound route-map on the vpnv4
>> iBGP connection to modify the next-hop of the vpnv4
>> video-dest-prefix to the new /32 
>> 
>> Would this work?
>> 
>> 	oli
>> 
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