We have recently converted our network from a combination of
bridged point-to-point and multiplexed analog services to a
routed Frame Relay network.  We use Cisco 2503 routers at 18
remote sites and a 4500 at the hub site. We're running
EIGRP, using variable subnetting with 6 Class C addresses
and routing protocol (no static routes) with bridging on for
our DTC traffic.  For reasons I won't get into we brought
the network up with 28K (CIR) PVC connections. We map these
to 2 T-1 FR services at the hub location. Our bridged
traffic worked well with this topology and our hope was to
add 1 or 2 public access Internet workstations at each
remote site (branch libraries). However, the addition of
just 1 Internet workstation at a given remote location has
created performance problems related to the bridged traffic.

We are now in the throes of upgrading our remote site FR
facilities to 128K (CIR) and adding a 3rd T-1 at the central
location in an attempt to address the bandwidth problem. We
are also considering allocating separate PVCs to support the
bridging independently of the TCP/IP traffic (Note:
Approximately 90% of our user equipment is serially
connected.).  So, we would have a 128K PVC to support the
TCP/IP traffic and a 28K PVC to support DTC traffic.  The
goal here is to isolate the DTC traffic and assure that it
always has sufficient dedicated bandwith for access to our
HP3000 running our automated library system (our primary
public service tool).

With that all said, does anyone with a similar environment
have statistical or anecdotal information about how much
bandwith is sufficient for a given number of heavily used
Internet workstations (i.e., how many Netscape workstations
can I reasonably expect to support with a 128K PVC)?

Critical assessment of this briefly described network and
any other related information is also welcome.

Thanks,
Steve


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Steven P. Barrett                 (703) 222-3132 - voice
Systems Analyst                   (703) 222-3135 - FAX
Fairfax County Public Library     [log in to unmask]
Technical Operations Center
4000 Stringfellow Rd.
Chantilly, VA  20151

--- The opinions expressed here are mine alone . ---
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