Only two VRFs, default and manangement. IIRC, everything I saw before mentioned the default VRF.
I do see a ton of route-maps. It's mostly Greek to me, so I'll have to dig through this a bit to see what's going on.
From: "Matthew Huff" <
mhuff@ox.com>
To: "Mike Hammett" <
nanog@ics-il.net>
Cc: "NANOG" <
nanog@nanog.org>
Sent: Monday, April 3, 2023 8:06:51 AM
Subject: RE: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging
What about VRFs and/or policy based routing?
switch-core1# show vrf
VRF-Name VRF-ID State Reason
default 1 Up --
management 2 Up --
switch-core1# show route-map
route-map rmap_bgp_to_eigrp_b2b, permit, sequence 10
Match clauses:
interface: Ethernet1/33
route-type: internal
Set clauses:
metric 40000000 10 255 1 1500
route-map rmap_bgp_to_eigrp_b2b, permit, sequence 20
Match clauses:
interface: Ethernet1/34
route-type: internal
Set clauses:
metric 40000000 30 255 1 1500
route-map rmap_static_to_eigrp, permit, sequence 10
Match clauses:
ip address prefix-lists: prefix_static_to_eigrp
Set clauses:
route-map rmap_static_to_eigrp_v6, permit, sequence 10
Match clauses:
ipv6 address prefix-lists: prefix_ipv6_static_to_eigrp
Set clauses:
From: Mike Hammett <
nanog@ics-il.net>
Sent: Monday, April 3, 2023 9:00 AM
To: Matthew Huff <
mhuff@ox.com>
Cc: NANOG <
nanog@nanog.org>
Subject: Re: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging
It could be an sFlow bug, but I come at this from a reported problem and gathering data on that problem as opposed to looking at data for problems.
The snmp if index reported by the Nexus matches the if index in ElastiFlow.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.comMidwest-IX
http://www.midwest-ix.com________________________________________
From: "Matthew Huff" <mailto:
mhuff@ox.com>
To: "Mike Hammett" <mailto:
nanog@ics-il.net>
Cc: "NANOG" <mailto:
nanog@nanog.org>
Sent: Monday, April 3, 2023 7:50:08 AM
Subject: RE: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging
SFlow misconfiguration or bug on either the nexus or the sflow monitor? On the monitor, can you verify that the snmp interfaces are mapped to the correct ones on the nexus?
From: Mike Hammett <mailto:
nanog@ics-il.net>
Sent: Monday, April 3, 2023 8:47 AM
To: Matthew Huff <mailto:
mhuff@ox.com>
Cc: NANOG <mailto:
nanog@nanog.org>
Subject: Re: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging
It shows the desired result.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.comMidwest-IX
http://www.midwest-ix.com ________________________________________
From: "Matthew Huff" <mailto:
mhuff@ox.com>
To: "Mike Hammett" <mailto:
nanog@ics-il.net>, "NANOG" <mailto:
nanog@nanog.org>
Sent: Monday, April 3, 2023 5:38:23 AM
Subject: RE: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging
switch-core1# sh forwarding route x.x.x.x
slot 1
=======
IPv4 routes for table default/base
------------------+-----------------------------------------+----------------------+-----------------+-----------------
Prefix | Next-hop | Interface | Labels | Partial Install
------------------+-----------------------------------------+----------------------+-----------------+-----------------
x.x.x.x/24 x.x.x.250 Ethernet1/29
switch-core1# show routing hash x.x.x.x y.y.y.y
Load-share parameters used for software forwarding:
load-share mode: address source-destination port source-destination
Hash for VRF "default"
Hashing to path *y.y.y.y Eth1/29
For route:
y.y.y.0/24, ubest/mbest: 1/0
*via z.z.z.z, Eth1/29, [90/3072], 1w2d, eigrp-100, internal
From: NANOG <mailto:
nanog-bounces+mhuff=
ox.com@nanog.org> On Behalf Of Mike Hammett
Sent: Monday, April 3, 2023 1:21 AM
To: NANOG <mailto:
nanog@nanog.org>
Subject: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging
We have a Nexus 3064 that is setup with partial BGP tables and is routing based on that.
I've done a show ip bgp for an IP of interest and it has an expected next hop IP. I show ip arp on that next hop IP and it has the expected interface.
However, sFlows show the packets leaving on a different interface, the one that would carry the default route for routes not otherwise known.
If the next hop IP is expected and the ARP of that next hop IP is expected, why are packets leaving out an unexpected interface?
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.comMidwest-IX
http://www.midwest-ix.com