Not logged in
Log in now
Create an account
Subscribe to LWN
LWN.net Weekly Edition for May 16, 2013
A look at the PyPy 2.0 release
PostgreSQL 9.3 beta: Federated databases and more
LWN.net Weekly Edition for May 9, 2013
(Nearly) full tickless operation in 3.10
What's so bad about IPv6?
Posted Jan 26, 2011 16:43 UTC (Wed) by mstefani (subscriber, #31644)
Some devices will support it only "in software"; hitting the CPU on a busy network devices is basically "game over". Other devices support IPv6 only in a limited way, e.g. no VRF support for IPv6. Of course for those type of problems the network vendors are more than happy to sell you new hardware for $$$ with a questionable ROI. But for some features your network might rely upon all you will get back is a "IPv6 support will be added next year"...
In theory, theory and practice are the same. In practice, they are not.
Posted Jan 26, 2011 17:36 UTC (Wed) by khim (subscriber, #9252)
No, they don't support it. It's easy, really: you claim that IPv6 is simpler to process and so it should provide performance boost. But let's check the facts
up to 60 million packets per second (Mpps) of IPv4 unicast forwarding traffic and up to 30 Mpps of IPv6 unicast forwarding traffic
Oops? Looks like simple and logical way to save half of equipment is to just disable IPv6 - and this is what ISPs are doing... It does not matter if hardware has support for IPv6 or not if it's disabled.
Posted Jan 26, 2011 19:06 UTC (Wed) by ebiederm (subscriber, #35028)
Posted Jan 26, 2011 21:40 UTC (Wed) by bronson (subscriber, #4806)
Posted Jan 27, 2011 13:51 UTC (Thu) by hmh (subscriber, #3838)
Being someone who has actually tried to do 10Gbps routing using Linux, I am well aware of its limitations. You need lots of tuning and the correct hardware to get high packets-per-second rates, and it gets nowhere close to the target 40Mpps. It really is useful only for large packets, or if you need nowhere near line-rate and don't care about DoS attacks with small packets.
One really needs hardware-assisted packet forwarding to do line-speed 10-gigabit routing at all packet sizes. Either that or a routing cluster, at which point TCO goes well above a proper 10Gbit Cisco/Juniper switch-router.
So, the question becomes: are there affordable, non-experimental hardware packet forwarding devices (preferably PCIe) that are compatible with Linux?
Posted Jan 26, 2011 20:08 UTC (Wed) by hmh (subscriber, #3838)
Copyright © 2013, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds