Re: NAV mac-search with Nexus and FabricPath

-- Mischa Diehm | Network Operations Center (NOC) UniBasel | UniRechenZentrum (URZ) Klingebergstr. 70 | CH-4056 Basel Tel. +41 61 267 1574 | http://urz.unibas.ch From: Mischa Diehm mischa.diehm@unibas.ch Date: Freitag, 4. April 2014 10:36 To: Morten Brekkevold morten.brekkevold@uninett.no Cc: "nav-users@uninett.no" nav-users@uninett.no Subject: Re: NAV mac-search with Nexus and FabricPath > 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.ht > ml > > 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 > > >