[Asterisk-Users] Snom firmwares suck <--additional datapoint to consider

[asterisk at anime.net]

On Fri, 26 May 2006, Rich Adamson wrote:
> Dr. Michael J. Chudobiak wrote:
>>> Blaming the 3com switch is very likely to be the wrong root cause. High 
>>> probability the 3com was not configured properly for the phone.
>> Just curious - what configuration issues did you have in mind?
> A partial list of issues that we've seen in the last 12 years include:
> - auto negotiation of duplex settings (mismatch)
> - spanning tree disabling ports for first 30 seconds after any link state 
> change (some attached devices don't like that)
> - spanning tree loops that end up isolating devices from the backbone 
> (spanning tree is usually implemented by the manufacture by default)
> - various switch manufacturers have licensed/implemented cisco's discovery 
> protocol, and the user doesn't realize some equipment attached to such ports 
> actually use the cdp data to change port configuration, while other devices 
> might barf on those packets.
> - assumptions that all switches operate at wire speeds and "buffer" packets 
> (eg, no such thing as a switch buffer; packets will be dropped under high 
> load conditions)
> - distributing vlans across multiple switches where assumptions are made 
> relative to what happens when two or more vlans are transporting traffic 
> volumes that when combined exceed a trunk's port speed (eg, don't forget 
> about broadcast storms).
> - switch forwarding tables that are too small (eg, workgroup switches) and 
> the table fills, essentially turning the switch into a hub
> - bad assumptions relative to rate limiting broadcast and multicast packets, 
> and how that impacts normal traffic.
> - etc, etc.

If any of these issues makes a _phone reboot or lockup_ then that is a 
serious flaw with the phone.

I migh expect a cheapy grandstream to have issues but expensive snom 
should really do better.

-Dan