Is there any recommendation on Ratio between number of
radius accouting server and number of radius
authentication server, if accouting and authentication
are executed by different hardware platform ?
Is there any way to estimate the burst rate of radius
protocol packet in ISP network?
thanks in advance.
Joe
Is there any recommendation on Ratio between number of
radius accouting server and number of radius
authentication server, if accouting and authentication
are executed by different hardware platform ?
I generally deploy just two accounting servers, because (most)
RADIUS-enabled devices deal with caching/retransmitting accounting
data in a reasonable fashion if the accounting servers are slow or
unresponsive -- users won't notice if Accounting is slow, quite the
opposite of Authentication.
Many (most?) RAS/VPN/etc devices only support configuring two RadAcct
servers, even devices which offer up to 4 total auth servers might
only allow 2 for accounting. Also keep in mind that some devices use
a primary/backup configuration, while other implementations send all
Accounting records to *both* servers at all times.
Is there any way to estimate the burst rate of radius
protocol packet in ISP network?
You can calculate your burst rate by either post-processing the RADIUS
event logs from the servers, or from NetFlow data. The real-world PPS
rate and BPS for RADIUS should be very low, even on a busy ISP -- our
biggest problem with RADIUS traffic isn't the traffic itself, but
rather giving the protocol priority on congested WAN links so it isn't
dropped by an oversubscribed router. Dropped packets are primarily a
problem for authentication requests, particularly if you're using
RADIUS with SecurID (due to the built-in multi-second delay ACE/Server
forces for all authentication requests, RADIUS or otherwise).
Kevin
We establish two server farm which service on two IP.
BAS use that two IP as AAA server addresses.
Currently , number of accouting server is much less
than authentication server although DB connection
allocated to accouting server is nearly the same to
authentication servers.
The problem is, radius server responding speed may
become very slow ( more than 100s) at peak time. some
of radius accouting packets overflows when they are
sent to radius server process queue. As radius
responding speed is slow, BAS retransmit those packets
in queue, the system performance worsen for
duplicated packets. some dial-session is not closed
normally because Accouting-off packets are lost or
overflowed.
I plan to deal with the problem by starting at
incoming packets rate measurement, and server
structure optimization. But, there seems to be too
few material available.
Joe