17 messages in org.freebsd.freebsd-archARP request retransmitting| From | Sent On | Attachments |
|---|---|---|
| Gleb Smirnoff | Nov 7, 2005 6:04 am | |
| Gleb Smirnoff | Nov 7, 2005 6:28 am | |
| Robert Watson | Nov 7, 2005 6:40 am | |
| Gleb Smirnoff | Nov 7, 2005 6:52 am | |
| Bill Vermillion | Nov 7, 2005 7:19 am | |
| Chuck Swiger | Nov 7, 2005 8:16 am | |
| Garance A Drosihn | Nov 7, 2005 9:49 am | |
| Peter Jeremy | Nov 7, 2005 9:55 am | |
| Gleb Smirnoff | Nov 7, 2005 11:41 am | |
| John-Mark Gurney | Nov 7, 2005 2:44 pm | |
| Charles Swiger | Nov 7, 2005 3:18 pm | |
| John-Mark Gurney | Nov 7, 2005 3:45 pm | |
| Charles Swiger | Nov 7, 2005 4:49 pm | |
| Peter Jeremy | Nov 8, 2005 1:11 am | |
| Bruce M Simpson | Nov 11, 2005 6:09 am | |
| Gleb Smirnoff | Nov 11, 2005 6:15 am | |
| Peter Wemm | Dec 27, 2005 12:22 pm |
| Subject: | ARP request retransmitting | |
|---|---|---|
| From: | Bill Vermillion (bv...@wjv.com) | |
| Date: | Nov 7, 2005 7:19:23 am | |
| List: | org.freebsd.freebsd-arch | |
On Mon, Nov 07, 2005 at 17:04 , the primordial soup was bombarded with cosmic radiation and a new life form of genus Gleb Smirnoff emerged to test its air breathing capabilities and with great effort gasped:
Colleagues,
I have a proposition on changing the behavior of ARP retransmitting. Currently we after sending several ARP requests, sending ARP requests for given IP is suppressed for some interval (by default 20 seconds). Probably this feature was designed in early 90th, when sending one additional broadcast packet was an expensive thing.
The man page says the host is considered down "for a short period (normally 20 seconds), allowing an error to be returned to transmission attempts in this interval".
I suggest to keep sending ARP requests while there is a demand for this (we are trying to transmit packets to this particular IP), ratelimiting these requests to one per second. This will help in a quite common case, when some host on net is rebooting, and we are waiting for him to come up, and notice this only after 1 - 20 seconds since the time it is reachable.
Any objections?
Is the 20 second limit that much of a problem. And the 20 minute timeout for caching is certainly far more generous that my old big Cisco that had a 4 hour cache. A user complained that he put up new machines and things weren't working. I told him he should have called me before he put the IPs back the way they were as cleanring the arp-cache took care of that.
How big is your network?
Bill
-- Bill Vermillion - bv @ wjv . com