We were pushing about 1.1mbps on the single T1 to C&W on an IRX-114. That
was all it could handle. Yes, it can do a full T1 between two locations,
but the sheer number of packets for a ISP router caused it to start having
packet loss at the levels described. We were getting 2-9% packet loss at
1.1-1.2mbps (in both directions simultaneously) Nothing else was on the
IRX. It came on so sudden, we thought it might have been a C&W problem,
but it was just a result of some sort of threshold as our bandwidth needs
have grown quite recently.
We had a script do a lot of pings across the router link and write the
output to a webpage, so we could keep track of it over several months,
thus our notice of recent packet loss.
I replaced the IRX-114 with a pm3 2-T1 version. The pm3 has 3.8.2c2 (not
that the modem code makes any difference), and a 32mb ECC ram chip I stole
from an alpha UDB. The memory as I understand does not provide any
performance changes, but makes room for BGP and OSPF which I'll likely
need in the future.
The last 8 hours (heavy evening use) has been 0% packet loss so far,
determined at 15 minute intervals of a series of pings. It used to be the
worst time of packet loss. If it stays clean like this, I will hook up the
second T1 port to a T1 feeding one of our pops.
We will still use IRXs in places where the packet-flow is not as
demanding, such as to our many small pops, but not where dialup traffic
exceeds a megabit.
On the IRX, we ocassionally got receive buffer full messages. I did notice
that the pm3 has 2800 system nbuffs total, and the IRX only has 1100 ish.
It's also fact that the pm3 has a much faster CPU. The pm3 also handles
things in a different manner- more distributed/modularized compared to the
IRX.
How much more powerful is the PM3 than the IRX for routing T1s? Is it 2x
more? Is it 10x more? Any crude estimates?
While I'm asking questions, is there hope for something bigger than a pm3,
but not as big as a pm4? Sort of a midsized router box? (Cisco resellers ;
don't even bother to email me your Cisco solution to the question, I am
aware of their product lines.)
THANKS,
Jason
-- /* Jason Philbrook | Midcoast Internet Solutions jp@midcoast.com | Internet Access, LAN, WAN, and Linux www.midcoast.com/jp/ | Service and Consulting for Midcoast Maine */- To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message. Searchable list archive: <URL:http://www.livingston.com/Tech/archive/>