nanog mailing list archives
Re: Big Temporary Networks
From: Seth Mos <seth.mos () dds nl>
Date: Wed, 19 Sep 2012 09:24:53 +0200
Op 18-9-2012 22:50, William Herrin schreef:
Yes, radvd has a configuration option to send unicast packets. But I think the effects are slightly overstated.On Tue, Sep 18, 2012 at 4:31 PM, Nick Hilliard <nick () foobar org> wrote:On 18/09/2012 21:24, William Herrin wrote:IPv6 falls down compared to IPv4 on wifi networks when it responds to a router solicitation with a multicast (instead of unicast) router advertisement.You mean it has one extra potential failure mode in situations where radio retransmission doesn't deal with the packet loss - which will cause RA to retry. "Fall down" is a slight overstatement.Potayto, potahto. Like I said, I have no interest in defending IPv6. But I'm very interested in how to implement an IPv6 network that's as or more reliable than the equivalent IPv4 network. That makes me interested in the faults which get in the way. Regards, Bill Herrin
Unless someone fudged the lifetime counters on the ra config nobody will ever notice a RA getting lost. Once every few seconds a RA message will be sent and it will be valid for atleast a couple of minutes. Within that time there will be multiple RA announcements, and unless you missed 5 minutes of RA advertisements everything is fine.
And if you do miss 5 minutes of RA multicast traffic, really, you have bigger problems. I see network stacks springing to life in the space of 3 seconds on the 1st message I send out. That's pretty stellar, and faster then some clients perform the DHCPv4 request.
Also note that some wifi networks eat DHCPv4 broadcasts too, which is pretty much the same deal as what you are referring to above. They will retry the DHCPv4 request, and so do client that perform router sollicitation requests. No different.
And if the wifi network is so bad that you have icmp and udp dropping like mad, I doubt anybody would want to use it. You are more likely that they will disable wifi altogether and use 3g. The 2.4Ghz wifi band is so crowded now that this has become the effective standard. Unless you are a happy camper that actually has a wifi card that supports the 5Ghz band. Which is far too uncommon in phones and tablets. boo.
Cheers, Seth
Current thread:
- Re: Big Temporary Networks, (continued)
- Re: Big Temporary Networks Masataka Ohta (Sep 16)
- Re: Big Temporary Networks Nick Hilliard (Sep 16)
- Re: Big Temporary Networks Masataka Ohta (Sep 16)
- Re: Big Temporary Networks Nick Hilliard (Sep 17)
- Re: Big Temporary Networks Masataka Ohta (Sep 17)
- Re: Big Temporary Networks William Herrin (Sep 17)
- Re: Big Temporary Networks Masataka Ohta (Sep 18)
- Re: Big Temporary Networks William Herrin (Sep 18)
- Re: Big Temporary Networks Nick Hilliard (Sep 18)
- Re: Big Temporary Networks William Herrin (Sep 18)
- Re: Big Temporary Networks Seth Mos (Sep 19)
- Re: Big Temporary Networks Masataka Ohta (Sep 19)
- Re: Big Temporary Networks Sean Harlow (Sep 19)
- Re: Big Temporary Networks Masataka Ohta (Sep 19)
- Re: Big Temporary Networks Valdis . Kletnieks (Sep 19)
- Re: Big Temporary Networks Masataka Ohta (Sep 19)
- Re: Big Temporary Networks TJ (Sep 19)
- Re: Big Temporary Networks Masataka Ohta (Sep 19)
- Re: Big Temporary Networks William Herrin (Sep 19)
- Re: Big Temporary Networks Masataka Ohta (Sep 19)
- Re: Big Temporary Networks TJ (Sep 19)