I do fully agree with you, Rick. I have another question though and this one makes things even more complicated.
One session between two LSRs is sufficient when using per-platform label space. Now, lets assume R1 has two parallel links to R2. LDP RIDs are set to the highest loopback IPs on both boxes. R2 is using physical interfaces as its transport-addresses, at the same time R1's default behavior remains unchanged (transport-address = LDP RID). R1 will try to establish two sessions to R2, R2 will attempt to have one active session to R1. What will happen in this scenario? How will session establishment look like? Which session should remain active? I know that in the case of two active sessions, the one sourced from higher IP remains active. Of course, I know that such config is a real mess and it won't work properly (I mean load-balancing) as one side thinks two sessions should be active, while the other assumes only one should be formed :-) On Wed, May 5, 2010 at 8:50 AM, Rick Mur <[email protected]> wrote: > It would work yes, you would have 1 LDP session between the routers with > multiple links between them. > Like you said, it complicates things a bit. It's hard to tell where the > labels come from and go to, but it definitely works :-) > > > -- > > Regards, > > Rick Mur > CCIE2 #21946 (R&S / Service Provider) > Sr. Support Engineer – IPexpert, Inc. > URL: http://www.IPexpert.com > > On 5 mei 2010, at 15:25, Adam wrote: > > Rick, > > Can't we use the same transport address on all links going to another LDP > router? I believe that using the same transport address (let's say another > (reachable) loopback) on both links going to the remote peer should work > (assuming we use per-platform label space). I know that only complicates > things and that's definitely not a best practice, but that should work > (neighbor LDP ID x reachable via src IP y (physical), transport IP = z > (loopback other than LDP RID). Correct me if I'm wrong, please. > > Thanks, > Adam > > On Wed, May 5, 2010 at 12:56 AM, Rick Mur <[email protected]> wrote: > >> In the first place I would never configure this in my lab, unless it's >> asked for! >> In 99% of the cases your loopback address (the default LDP Router ID) will >> be reachable for the other side via your IGP, so the TCP session for LDP >> will also be using the Loopbacks as source and destination address and the >> session will come up. So it's very important that your LDP Router ID is >> reachable for the other side. >> To overcome this issue (or when using multiple links and you want LDP >> load-balancing) you should use the interface address (which is ALWAYS >> reachable by the other side) to be the transport-address, meaning that it >> will not use the Router ID as source and destination, but use the interface >> addresses for the TCP session. >> >> I hope this answers your question. >> >> >> -- >> Regards, >> >> Rick Mur >> CCIE2 #21946 (R&S / Service Provider) >> Sr. Support Engineer – IPexpert, Inc. >> URL: http://www.IPexpert.com >> >> On 5 mei 2010, at 06:48, venkat wrote: >> >> > And this transport-address should be reachable from neighbor to form >> adjacency. >> > >> > On 5/5/10, Adam <[email protected]> wrote: >> >> It forces creation of LDP session using that particular >> address/interface >> >> (by default LDP RID is used). If there is more than one link to the >> other >> >> LDP router, you should use the same transport address. >> >> >> >> On Tue, May 4, 2010 at 2:40 PM, Mustafa Yadav >> >> <[email protected]>wrote: >> >> >> >>> hi guys >> >>> >> >>> mpls ldp discovery transport-address interface >> >>> >> >>> Why the above command is so critical?Without this the ldp neighborship >> did >> >>> not come up/ >> >>> >> >>> _______________________________________________ >> >>> For more information regarding industry leading CCIE Lab training, >> please >> >>> visit www.ipexpert.com >> >>> >> >>> >> >> >> > >> > -- >> > Sent from my mobile device >> > _______________________________________________ >> > For more information regarding industry leading CCIE Lab training, >> please visit www.ipexpert.com >> >> > >
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
