1 correction inlined. [Bruno2]
From: spring [mailto:[email protected]] On Behalf Of
[email protected]
Sent: Thursday, January 15, 2015 4:57 PM
[...]
This is the first issue.
(Non-SR)
S11-----------S12----------S13---------S14
| | | |
| | | |
| | | |
S21-----------S22----------S23---------S24
As above topoloby, there are 8 nodes and assume all the metics of the links are
1 and VPNs are deployed
on S11/S21/S14/S24.
If LDP is used as the tunnel for VPN on S11/S14, since LDP can support the
ordered mode. The LSP for the S14 will be
setup as the order S14->S13->S12->S11 for distribution of label mapping. And
the shortest path for routes
to S14 is also S11->S12->S13->S14. So the end-to-end LSP to S14 is setup. If
one node (e.g. S13) does not
support LDP, according to LDP ordered mode, the end-to-end LSP cannot setup
since S12 does not receive the label
mapping from the exact nexthop of the route, S13 and it will not distribute the
label mapping to S11. And the
result is that the VPN on S11 cannot take the LSP since the LSP cannot setup on
S11.
[Bruno]
My understanding of your case is the following, please correct me if I'm wrong:
There is no SPRING/SR. All nodes support LDP. S11, S12, S14 use ordered mode.
S13 use independent mode.
First, such cases happen today in multiple vendor networks since different
implementation used different options.
Then, I believe that your understanding of LDP independant mode is incorrect.
In independent mode, S13 always advertises the S14 FEC to its neighbor, even if
it don't gets a label mapping from its downstream S14. This FEC is then
propagated to S11 in ordered mode.
As a result, S11 gets a label for S14 and will use S14 for the VPN. However in
the forwarding plane the traffic will be dropped on S13.
[Bruno2] I withdraw my last sentence. In this fist cast, traffic is not
dropped. It works fine. We only lose the propagation of LDP FEC status in the
control plane.
_________________________________________________________________________________________________________________________
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.
_______________________________________________
spring mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/spring
