Updated PR for get_bgp_neighbors to support IPv6

[ktbyers]

No description provided.

[ktbyers]

cc: @benmaddison

[ktbyers]

@mirceaulinic or @dbarrosop or @ebeahan ...one of you should also review this (as I made quite a few modifications to it).

I have reviewed the original work pretty extensively (so main requirement is to review my changes).

[coveralls]

Coverage increased (+2.7%) to 70.191% when pulling c30df8c on get_bgp_neighbors_pr into 094a60d on develop.

[ktbyers]

The CI issue looks like a Travis-CI issue with Python3.5 (Python3.4 works...so I think we should be good there).

[benmaddison]

@ktbyers on your question RE: merging the is_up and uptime values across different AFIs using OR and MAX, respectively:
I did it this way because I interpret the resulting fields in the .get_bgp_neighbors() return dict as referring to the state of the session itself, not of the individual AFIs negotiated within the session.
It is possible, for example, to have ipv4 in Established and ipv6 in NoNeg, in which case returning is_up = False for the session seems misleading.
I think that the real fix for this should be to provide the ability for the method to return per-AFI state: but that obviously needs to change library wide, not just in napalm-ios.

[ktbyers]

Yes, agreed that separate reflection of is_up and uptime per AFI would be better. This will change in napalm-yang so I don't think it makes sense to update here.

@mirceaulinic @dbarrosop What are your thoughts on the issue of is_up / uptime across both AFI of IPv4 and IPv6. I still think a logical-or and minimum uptime is the more conservative approach. I.E. if you configured them both then if both of them are not up, reflect is_up as down (and use the minimum uptime).

[coveralls]

Coverage increased (+2.7%) to 70.145% when pulling c833d4d on get_bgp_neighbors_pr into 094a60d on develop.

[coveralls]

Coverage increased (+2.7%) to 70.145% when pulling c833d4d on get_bgp_neighbors_pr into 094a60d on develop.

[dbarrosop]

is_up and uptime are related to the BGP session which is independent from the AFI. NoNeg is actually a "negotiation" capability mismatch (not really a session issue) so there are a few things we can do:

1. First, a logical OR is the right solution here as the session can't be up for IPv4 and down for IPv6. Same for other AFIs/SAFIs. There is only one session.
2. Now, we probably want to signal if an AF is negotiated or not. We have two solutions IMHO:
   a. Easiest would be to not return it at all. After all, get_bgp_neighbors returns state, not configuration.
   b. Alternatively, we could also discuss adding a capabilities field where we list which capabilities were negotiated successfully.

[coveralls]

Coverage increased (+2.7%) to 70.199% when pulling d66a69a on get_bgp_neighbors_pr into 094a60d on develop.

[ktbyers]

@dbarrosop @benmaddison Okay, I converted is_up back to a logical or and I changed uptime back to max.

Realistically, the up_time and is_up should be essentially the same for both AFIs (except possibly for transition events...i.e. we query IPv4, and then the session goes down, then we query IPv6).

I also changed 'is_up' to be based on uptime and not to be based on state/prefixes field (as NoNeg state would previously flag BGP session as down even though it was up).

Here is an example:

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
xxxx:xxx:61F::11   4   701  251053  262007        0    0    0 00:04:51 (NoNeg)
xx.xx.228.5    4   701 5404546  267918      105    0    0 00:22:44        6

I also converted the no-value for accepted/received/sent prefixes to be -1 (since zero can be a valid value when the session is up).

Note, I am going to move this and track it as a separate issue. Basically, I think the current code is a significant improvement over what we previously had and I think we should move forward with it. Then we can separately address what do with respect to an address family not being negotiated.

Now, we probably want to signal if an AF is negotiated or not. We have two 
solutions IMHO:
a. Easiest would be to not return it at all. After all, get_bgp_neighbors returns state, 
not configuration.

[coveralls]

Coverage increased (+2.7%) to 70.174% when pulling a4a50c2 on get_bgp_neighbors_pr into 094a60d on develop.

[dbarrosop]

I agree. Approved :)