Re: [Isis-wg] draft-ginsberg-isis-l2bundles

["Les Ginsberg (ginsberg)" <[e-mail]>]

Stephane –

I guess I don’t understand what you mean when you say:

“With solution #4, you have the choice per protocol/application to use the LAG or individual interfaces.”

Do you mean that it is not necessary to have L3 adjacencies on all interfaces? If so, even with the solution defined in the draft it is a local matter as to what L2 bundle members are advertised. It could be all of them or a subset – that is a matter for local configuration and does not need to be standardized. This is why I said your new column seems no different than Ahmed’s existing column 3 – other than perhaps you are suggesting we should not use unnumbered – in which case I think you have made using L3 adjacencies more onerous.

Please clarify.
Thanx.

   Les


From: [e-mail] [mailto:[e-mail]]
Sent: Monday, August 17, 2015 8:17 AM
To: Les Ginsberg (ginsberg); Ahmed Bashandy (bashandy); Acee Lindem (acee); Ebben Aries; [e-mail] list ([e-mail])
Subject: RE: [Isis-wg] draft-ginsberg-isis-l2bundles


Les,

I thought that column #3 was using L3 bundles with unnumbered interfaces, and in this case you loose the ability to hide topology to some protocols : all layer 3 protocols see individual links. With solution #4, you have the choice per protocol/application to use the LAG or individual interfaces.


As I mentioned in my previous mail, here are my comments :

Column#3 scaling :  it adds some adjacencies, but honestly I don’t think today this is an issue with controlplane resources we have and multithreading. But yes there is an additional cost.


In the table, you can also add  a section regarding failure detection :
As for solution #1 (L2 bundles in ISIS) and solution #2 (BGP-LS), you need a mechanism outside the protocol to monitor the status on each individual link and report it to the protocol which requires to implement something in addition (it does not work by itself), solution#3 and #4 (see above) : ISIS hellos are doing the job if fast detection is not required.


Regarding the risk :
What is the risk to deploy BGP-LS ? It’s an operational cost (and you already count it before) but IMO there is no risk associated with. Do you know networks that would use this feature and that does not have already a BGP controlplane ?
For column#3, all the individual links have to be seen by the management system, so whatever they are L2 or L3, there is no scaling issue here.

Column#3 impact on base routing, what is the impact on the base routing ?

Regarding the criteria : “Using 1 protocol for diverse functionalities”, This is always counted in “Mandate the deployment of a protocol that was not deployed before” moreover using IMO, 1 protocol to do everything is never good … (like using a single router to do every features ☺ )



Best Regards,

Stephane


From: Les Ginsberg (ginsberg) [mailto:[e-mail]]
Sent: Monday, August 17, 2015 16:41
To: LITKOWSKI Stephane SCE/IBNF; Ahmed Bashandy (bashandy); Acee Lindem (acee); Ebben Aries; [e-mail]<mailto:[e-mail]> list ([e-mail]<mailto:[e-mail]>)
Subject: RE: [Isis-wg] draft-ginsberg-isis-l2bundles

Stephane –

Your new column is already covered by Ahmed’s column #3: “L2 bundles as unnumbered interfaces in ISIS”

Problem is – the two of you disagree on what is +/- for a number of rows.

I don’t think assigning addresses for a much larger set of interfaces (e.g. if there are 128 bundle members this is 128 * the number of L3 interfaces) should be considered easy to do – which is why Ahmed suggested using unnumbered.

Perhaps you could explain why you disagree with Ahmed’s assessment of the rows for his column #3??

    Les



_________________________________________________________________________________________________________________________



Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc

pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler

a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration,

Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci.



This message and its attachments may contain confidential or privileged information that may be protected by law;

they should not be distributed, used or copied without authorisation.

If you have received this email in error, please notify the sender and delete this message and its attachments.

As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified.

Thank you.