On Mon, Sep 22, 2008 at 06:47:39AM +0800, Alastair Johnson said:
Are there any plans for the NZ IXs to be jumbo-capable?
Yup. In the list of design aims for the IX networks, it's not at the top of the list, but it's not at the bottom either. As most modern gear supports large frames, it is largely happening as a function of normal switch replacement. All switches deployed in the last couple of years on the APE and WIX fabrics support 1998 bytes (at 10/100Mb) and (at least) 9000 bytes for 1000Mb. That doesn't necessarily mean, though, that you'll get those MTU's across the exchanges - sometimes we do things that steal bytes, and there are still some older switches around with lower limits (particularly Cisco 2950's, which are 1500 bytes for all ports, and 3550's, which are ~2000 bytes on all ports). Right now, I think you'll get 9000 bytes on customer facing GE ports on APE, 2000 on WIX, and 1500 bytes on 100Mb ports on both IX's. I haven't tested, that, though, so YMMV. In Auckland, I believe the core is 9000 byte safe, but there are a bunch of 2950's strewn around the edge that will limit to 1500 bytes. There is no fixed plan to pull them out - they'll be replaced as demand dictates. In Wellington, there are less edge 2950's, but there are a dozen switches in the core which need to be replaced before we can carry
2000 bytes. I hope we'll have the majority of that work done by the end of the year, but it'll depend on what other work the outside plant guys have on.
So right now, if >1500 byte frames are a requirement, it's always good to mention that when you are ordering a new port, just to remind the provisioning guys that the 2950's really do need to be thrown in the harbour.
I'd be interested in hearing from anyone who is jumbo-enabled on their transit connections, and particularly interested in hearing if they are seeing any significant number of packets that are >1500B on the Internet.
From a random port on APE:
Transmit TenGigabitEthernet1/0/2 Receive 842676042645 Bytes 30787514711 Bytes 4126605040 Unicast frames 2466873557 Unicast frames 320790489 Multicast frames 14490379 Multicast frames 112278583 Broadcast frames 16399379 Broadcast frames 0 7 collision frames 1674685453 Minimum size frames 0 8 collision frames 3808990723 65 to 127 byte frames 0 9 collision frames 3681511885 128 to 255 byte frames 0 10 collision frames 1316050645 256 to 511 byte frames 0 11 collision frames 2871906426 512 to 1023 byte frames 0 12 collision frames 2013979673 1024 to 1518 byte frames 0 VLAN discard frames 15540398 Valid frames, too large 610595605 64 byte frames 0 Valid frames, too small 2052662643 127 byte frames 2861097914 255 byte frames 0 Too old frames 2208233399 511 byte frames 0 Valid oversize frames 23308406 1023 byte frames 0 System FCS error frames 1081047305 1518 byte frames 0 RxPortFifoFull drop frame 11015598 Too large frames I'm not quite sure how to intepret that, as the frame size breakdowns don't seem to sum to the rx/tx totals, but in any case, large frames don't appear to be a significant proportion (but they are non zero, and I'd imagine that proportion is climbing). Cheers Simon