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Re: Is arpresolve() good to get ARP started on an IP address?
- From: Andrew Lunn <andrew at lunn dot ch>
- To: Tad <ecos_removethispart at ds3switch dot com>
- Cc: eCos Disuss <ecos-discuss at ecos dot sourceware dot org>
- Date: Wed, 20 Jun 2007 23:45:59 +0200
- Subject: Re: [ECOS] Is arpresolve() good to get ARP started on an IP address?
- References: <46783A66.4040503@ds3switch.com> <20070619192426.GF24842@lunn.ch> <4678630E.3050406@ds3switch.com>
On Tue, Jun 19, 2007 at 03:13:18PM -0800, Tad wrote:
> Andrew Lunn wrote:
> >On Tue, Jun 19, 2007 at 12:19:50PM -0800, Tad wrote:
> >
> >>SNMP agent is dropping coldstart and LinkUp traps since ARP table comes
> >>up without entries
> >>
> >
> >Maybe i don't understand what you are saying, but if there is no ARP
> >entry, the IP packet which needs to be sent is normally queued and an
> >ARP request is sent out. Once an ARP reply is received the queues
> >packet is then sent. Is this not happening?
> ARP will only que one mbuf, then drops it if more come in If a
> coldstart and 2 link-up traps occur at powerup, and if we have 2
> trapsinks, for example, that's 6 msgs of which 4-5 are dropped. I need
> to update the ipdropped snmp stats counter too, cause it took awhile to
> figure out where the missing packets were going. Looked tricky to use
> arpresolve? without dropping any mbuf queued there also.
Ah, O.K. Well, two comments:
SNMP is designed to be unreliable. It uses UDP. So this is acceptable
behaviour.
You could change the single mbuf into a queue. All the macros to do
this exist, so i doubt it would be too big a job.
Andrew
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