<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size: 14px; font-family: Calibri, sans-serif; "><div>Of course some of us still have a few POS interfaces with 4470 byte restrictions so while 9216 is great, it's pretty hard to promise it network wide unless there is a specific requirement to migrate all services to support it.</div><div><br></div><div>In my experience, permitting IP transit with larger than 1500 byte MTUs also led to some strange jumbo frame issues where the customer has their own switched network between their provider and themselves and they haven't properly configured it to handle the larger frame sizes.</div><div><br></div><div>The path of least resistance was just to set "ip mtu 1500" as standard on all customer-facing IP transit services, IP transit points and peering points.</div><div><br></div><div>Macca</div><div><br></div><div><br></div><div><br></div><span id="OLK_SRC_BODY_SECTION"><div style="font-family:Calibri; font-size:11pt; text-align:left; color:black; BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt"><span style="font-weight:bold">From: </span> Lincoln Dale <<a href="mailto:ltd@aristanetworks.com">ltd@aristanetworks.com</a>><br><span style="font-weight:bold">Date: </span> Thu, 2 Feb 2012 17:10:30 +1100<br><span style="font-weight:bold">To: </span> "Sean K. Finn" <<a href="mailto:sean.finn@ozservers.com.au">sean.finn@ozservers.com.au</a>><br><span style="font-weight:bold">Cc: </span> "<a href="mailto:Ausnog@ausnog.net">Ausnog@ausnog.net</a>" <<a href="mailto:Ausnog@ausnog.net">Ausnog@ausnog.net</a>><br><span style="font-weight:bold">Subject: </span> Re: [AusNOG] MTU Size on Ethernet carrier interconnects<br></div><div><br></div>In a world of utopia, everyone would just enable 9216 byte jumbo frames & be done with it.<br>the reality is that a variety of 'ethenet' WAN services are implemented using a variety of silicon which predates 9K jumbo frames, and some have silicon that only enables 1500 byte or at best a 'baby giant' frame.<br><br>i doubt anyone has <1500 byte. thats not so useable. :)<br><br><br>cheers,<br><br>lincoln.<br><br>-- <span><font color="#888888"><br><span><font color="#888888">Lincoln Dale | Principal Engineer | Arista Networks<br><a href="mailto:ltd@aristanetworks.com" target="_blank">ltd@aristanetworks.com</a> | <a value="+14085475782">+1 408 547 5782</a> | <a value="+61417457965">+61 417 457 <span>965</span></a>
<br><br></font></span></font></span><br><div class="gmail_quote">On Thu, Feb 2, 2012 at 5:05 PM, Sean K. Finn <span dir="ltr"><<a href="mailto:sean.finn@ozservers.com.au">sean.finn@ozservers.com.au</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div link="blue" vlink="purple" lang="EN-US"><div><p class="MsoNormal"><span style="color:#1f497d">Flooded with private replies, thanks to all.<u></u><u></u></span></p><p class="MsoNormal"><span style="color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="color:#1f497d">General consensus is minimum 1500MTU but many providers will do slightly higher, and some very very much higher.<u></u><u></u></span></p><p class="MsoNormal"><span style="color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="color:#1f497d">S.<u></u><u></u></span></p><p class="MsoNormal"><span style="color:#1f497d"><u></u> <u></u></span></p><div><div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; ">From:</span></b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; "> <a href="mailto:ausnog-bounces@lists.ausnog.net" target="_blank">ausnog-bounces@lists.ausnog.net</a> [mailto:<a href="mailto:ausnog-bounces@lists.ausnog.net" target="_blank">ausnog-bounces@lists.ausnog.net</a>] <b>On Behalf Of </b>Sean K. Finn<br><b>Sent:</b> Thursday, February 02, 2012 2:46 PM<br><b>To:</b> '<a href="mailto:Ausnog@ausnog.net" target="_blank">Ausnog@ausnog.net</a>'<br><b>Subject:</b> [AusNOG] MTU Size on Ethernet carrier interconnects<u></u><u></u></span></p></div></div><div><div class="h5"><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">G’day all.<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">What’s considered a standard MTU size for bulk IPv4 Transit when delivered via Ethernet? (Assume as an Access port, not a trunk port).<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">Cheers,<u></u><u></u></p><p class="MsoNormal">Sean.<span style="font-size: 12pt; font-family: 'Times New Roman', serif; " lang="EN-AU"><u></u><u></u></span></p><p class="MsoNormal"><u></u> <u></u></p></div></div></div></div><br></blockquote></div><br>
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