<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:Helvetica;
panose-1:2 11 6 4 2 2 2 2 2 4;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoNormal">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?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> Mike Hammett <nanog@ics-il.net> <br>
<b>Sent:</b> Monday, April 3, 2023 8:47 AM<br>
<b>To:</b> Matthew Huff <mhuff@ox.com><br>
<b>Cc:</b> NANOG <nanog@nanog.org><br>
<b>Subject:</b> Re: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">It shows the desired result.<o:p></o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"><br>
<br>
-----<br>
Mike Hammett<br>
Intelligent Computing Solutions<br>
<a href="http://www.ics-il.com">http://www.ics-il.com</a><br>
<br>
Midwest-IX<br>
<a href="http://www.midwest-ix.com">http://www.midwest-ix.com</a><o:p></o:p></span></p>
</div>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<div class="MsoNormal" align="center" style="text-align:center"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">
<hr size="2" width="100%" align="center" id="zwchr">
</span></div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:black">From:
</span></b><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:black">"Matthew Huff" <<a href="mailto:mhuff@ox.com">mhuff@ox.com</a>><br>
<b>To: </b>"Mike Hammett" <<a href="mailto:nanog@ics-il.net">nanog@ics-il.net</a>>, "NANOG" <<a href="mailto:nanog@nanog.org">nanog@nanog.org</a>><br>
<b>Sent: </b>Monday, April 3, 2023 5:38:23 AM<br>
<b>Subject: </b>RE: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging<br>
<br>
switch-core1# sh forwarding route x.x.x.x<br>
<br>
slot 1<br>
=======<br>
<br>
<br>
IPv4 routes for table default/base<br>
<br>
------------------+-----------------------------------------+----------------------+-----------------+-----------------<br>
Prefix | Next-hop | Interface | Labels | Partial Install
<br>
------------------+-----------------------------------------+----------------------+-----------------+-----------------<br>
x.x.x.x/24 x.x.x.250 Ethernet1/29 <br>
<br>
<br>
switch-core1# show routing hash x.x.x.x y.y.y.y<br>
Load-share parameters used for software forwarding:<br>
load-share mode: address source-destination port source-destination<br>
Hash for VRF "default"<br>
Hashing to path *y.y.y.y Eth1/29<br>
For route:<br>
y.y.y.0/24, ubest/mbest: 1/0<br>
*via z.z.z.z, Eth1/29, [90/3072], 1w2d, eigrp-100, internal<br>
<br>
<br>
<br>
<br>
From: NANOG <<a href="mailto:nanog-bounces+mhuff=ox.com@nanog.org">nanog-bounces+mhuff=ox.com@nanog.org</a>> On Behalf Of Mike Hammett<br>
Sent: Monday, April 3, 2023 1:21 AM<br>
To: NANOG <<a href="mailto:nanog@nanog.org">nanog@nanog.org</a>><br>
Subject: Cisco Nexus 3k Route Selection\Packet Forwarding Debugging<br>
<br>
We have a Nexus 3064 that is setup with partial BGP tables and is routing based on that. <br>
<br>
<br>
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. <br>
<br>
<br>
However, sFlows show the packets leaving on a different interface, the one that would carry the default route for routes not otherwise known. <br>
<br>
<br>
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? <br>
<br>
<br>
-----<br>
Mike Hammett<br>
Intelligent Computing Solutions<br>
<a href="http://www.ics-il.com">http://www.ics-il.com</a><br>
<br>
Midwest-IX<br>
<a href="http://www.midwest-ix.com">http://www.midwest-ix.com</a><o:p></o:p></span></p>
</div>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
</div>
</div>
</body>
</html>