I'm sure there's a date code, but I don't know what it is.
----- Mike Hammett Intelligent Computing Solutions http://www.ics-il.com ----- Original Message ----- From: "Shayne Lebrun via Af" <af@afmug.com> To: af@afmug.com Sent: Thursday, December 11, 2014 10:34:14 AM Subject: Re: [AFMUG] EoIP over fiber - high latency? With no sort of product revision code or other identifier. There are some things you can look at that will * probably * tell you, but nothing definitive short of logging in and looking. Also, you need a fairly recent firmware revision. From: Af [mailto:af-boun...@afmug.com] On Behalf Of Mike Hammett via Af Sent: Thursday, December 11, 2014 9:39 AM To: af@afmug.com Subject: Re: [AFMUG] EoIP over fiber - high latency? You have old, old units. The new ones do 2024 or better. Still Rocket Ms. They changed that 2 - 3 years ago. ----- Mike Hammett Intelligent Computing Solutions http://www.ics-il.com ----- Original Message ----- From: "Kade Sullivan via Af" < af@afmug.com > To: af@afmug.com Sent: Thursday, December 11, 2014 8:35:41 AM Subject: Re: [AFMUG] EoIP over fiber - high latency? So looks like this may be a reason not to use UBNT stuff for our backup links. Looks like the highest I can set the MTU is 1515 on a couple units and 1524 on another. Neither capable of 1528 or more. I'll have to find some brand new hardware and see if it can go higher. How big of a performance hit are we talking here? Potentially requiring double the pps to move the same amount of large packets? I could that potentially being a pretty big problem. On Wed, Dec 10, 2014 at 4:49 PM, Shayne Lebrun via Af < af@afmug.com > wrote: To my understanding, it works like this: Say you take an IP packet coming into ether1, and it’s full MTU; 1500 bytes. Now, you want to bridge ether1 to an EoIP tunnel. EoI is GRE, and there’s a 28 byte overhead for the GRE encapsulation. Now you have a 1528 byte packet. Unless every device between that router and the EoIP endpoint has layer2 MTUs of at least 1528 bytes, you’re going to transmit two packets to move that one original packet. One packet will have something like 1472 bytes of the original packet, plus GRE overhead for 1500, and one will have the remaining 28 bytes of the original packet, plus 28 GRE overhead, so, something like 56 bytes. This introduces the obvious slowdowns, as well as not so obvious ones, like maybe you have a device in the middle that’s not so good at PPS. Or that queues up small packets into one big air frame, and therefore you’re waiting for reassembly on the far end. Now, if you’re going from a 1500 byte LAN across a 9000 byte fiber connection, you’ll not notice this. If you’re going to a satellite office behind DSL with PPPoE, or a cable modem, or whatever, you’re going to notice. From: Af [mailto: af-boun...@afmug.com ] On Behalf Of Kade Sullivan via Af Sent: Wednesday, December 10, 2014 5:17 PM To: af@afmug.com Subject: Re: [AFMUG] EoIP over fiber - high latency? Could you elaborate on this? We have a couple EOIP links across "other" networks and have never adjusted the MTU anywhere. I just pulled up the EOIP interfaces on each router and they are all set for 1500. Should we be increasing this number as a best practice when building EOIP Tunnels? On Wed, Dec 10, 2014 at 3:52 PM, Shayne Lebrun via Af < af@afmug.com > wrote: Bear in mind that unless you’ve increased your MTU from end to end, or dropped the MTU on your two devices that the EoIP are bridging, you’re going to get packet fragmentation. Otherwise, what RouterOS version? From: Af [mailto: af-boun...@afmug.com ] On Behalf Of Erich Kaiser via Af Sent: Wednesday, December 10, 2014 4:25 PM To: af@afmug.com Subject: [AFMUG] EoIP over fiber - high latency? So I have an EoIP tunnel setup over two fiber connections for a customer, I am seeing high latency over the tunnel any idea? MTU Issue? Using RB1100AHx2 on both ends.
