Failover Peer Issue with Polycom SoundStation IP 6000 Phone

glenn.satchell at glenn.satchell at
Wed Nov 18 21:30:46 UTC 2020

So from the dhcp-eval man page the arguments to substring() are

        substring (data-expr, offset, length)

Note that the parameter hardware() is one byte for the network type (1 
for ethernet, but others include token ring, etc) prefixed to the MAC 
address. So for a device that has the mac address aa:bb:cc:dd:ee:ff, 
hardware() will return 01:aa:bb:cc:dd:ee:ff

The hardware string represents 7 bytes of data with each byte (or octet) 
being represented by two hexadecimal characters separated by a colon.

So for Q1, the last parameter is the length of the string to match.

And for Q2 matching on the first 4 bytes of the mac seems like the way 
to go, eg: if hardware() is as above then we want to match 1:aa:bb:cc:34 
which is a length of 5.

substring(hardware, 1, 5 = 1:aa:bb:cc:34)

or to ignore the network type, perhaps start at the second byte

substring(hardware, 2, 4 = aa:bb:cc:34)

Hope this helps.


On 2020-11-19 05:45, willieb wrote:
>>> substring(hardware, 1, 4 = 1:aa:bb:cc)
> I'm not sure who owned the lease, but I do believe the class solution 
> will
> be a nice workaround. I have 2 questions at the moment:
> 1.) Regarding the substring statement above, what is the difference in 
> using
> "1, 4" or "1, 3"?
> 2.) The first 6 digits of the mac address (OUI) is the same for all of 
> our
> Polycom phones, but it appears the SoundStations we have all use 34 as 
> the
> next 2 mac digits. So can we specify 8 digits instead of 6 digits for
> matching?
> Thanks.
> --
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