Hi,
On Mon, 31 Mar 2014 10:28:50 +0000 Mischa Diehm mischa.diehm@unibas.ch wrote:
we have FP activated in our datacenter and use Cisco Nexus (5,6,7)k. I'm not sure what caused the problem but NAV can't find MAC-addresses on these devices and even on catalysts behind them anymore. I don't know what algorithm is used to figure out where a MAC-address is attached but maybe someone who knows can clarify what is needed for that to work?
Not being a network engineer, I have no experience with FabricPath. I had to Google it, and from what I could glean from [1], it appears FabricPath throws traditional layer 2 bridging off the boat.
NAV collects MAC addresses from the forwarding tables in your switches. It appears that Cisco FabricPath doesn't using forwarding tables, but instead employs a proprietary system for routing ethernet frames.
In light of that, there is nothing the current version of NAV that will help you get layer 2 information out of this proprietary system. Cisco may have some MIBs available to get the relevant information, but I could not say how/when or if we would put support for in on our roadmap.
Cisco has released information for FP-MIBS under:
ftp://ftp.cisco.com/pub/mibs/v2/CISCO-FABRICPATH-TOPOLOGY-MIB.my ftp://ftp.cisco.com/pub/mibs/v2/CISCO-FABRICPATH-TOPOLOGY-CAPABILITY.my
Unfortunately I can't find any of this information supported on our Nexus 5K/6K yet.
ftp://ftp.cisco.com/pub/mibs/supportlists/nexus6000/Nexus6000MIBSupportList. html
Checking in a retrieved snmpwalk on a 6K. First check for a MAC-Adress behind a Portchannel trunk. Second grep for Mac behind a FabricPath Port:
root@m:~# grep -i "00 1e 7a cb d1 00" /root/tmp/nex6.txt iso.3.6.1.2.1.4.22.1.2.151060481.10.33.1.254 = Hex-STRING: 00 1E 7A CB D1 00 iso.3.6.1.2.1.4.35.1.4.151060481.1.4.10.33.1.254 = Hex-STRING: 00 1E 7A CB D1 00 iso.3.6.1.2.1.17.4.3.1.1.0.30.122.203.209.0 = Hex-STRING: 00 1E 7A CB D1 00 root@m:~# grep -i "00 50 56 b3 02 5a" /root/tmp/nex6.txt root@m:~#
This looks like the following running "show mac address-table" on the n6k:
* 3200 001e.7acb.d100 dynamic 40 F F Po2 * 3200 0050.56b3.025a dynamic 40 F F 1810.0.0
In the end of the second line 1810.0.0 is the FP ID of the neighbour n6k.
This said I guess once there is support for the MIBs it should be possible to retrieve and work with this information on NAV. What I don't understand is how NAV decides if the MAC is actually directly attached (Access Port Check?) and what the algorithm in place is. Finally it is not clear to me if it would be possible to adapt and include the FP information?
Cheers, Mischa