🚀 go-pugleaf

> We are considering a new network which connect all of our different
> sites through a WAN. We will probably buy some CISCO routers. 
> 
> The trafic which is routed through the CISCO equipment is split
> in two
> 
>        - FTAM trafic based on x25 connections             
>     
>        - Interactive terminal sessions based on TCP/IP on an Ethernet.
> 
> Like this:
> 
>                            IIIIIIIIIIIIIIII
>        FTAM/X25----------> I              I 
>                            I CISCO ROUTER I------- 2 MBit --->
>        TCP/IP/ETHERNET---> I              I
>                            IIIIIIIIIIIIIIII      
> 
>  
> The CISCO routers can mix these two kinds of input intp one 2Mbit channel
> which connects the different sites.
> 
> My concern is now : Will the interactive traffic suffer when a heavy
> FTAM transport is taking place ?. Will the file transfers affect the
> responsetimes for the interactive traffic to a large extend ?.
> 
> If YOU have any experience with this please E-mail (or fax) me the 
> information. Or if you have a reference to the litterature about this
> kind of setup I will appreciate that too. Or just youre opinion from
> your experience.

Hello Lars,

You can apply the "Priority Queueing" mechanisms on your outbound
interface on the router. With that, you can specify that, in case
of congestion, your IP traffic should take precedence over your OSI
traffic.

Priorities can be set based on protocol (IP, CLNS, DECNET, etc),
or application (specify TCP or UDP port numbers), or the interface
through which the packets entered the router, or the packet sizes.

Look for the keywords "priority-list" and "priority-group" in your
router manual.

Finally, please note that priority queueing is mostly useful on
"low-speed" interfaces (+/- up to 64Kbps), which are likely to
be congested. Be sure the extra overhead introduced by priority
queueing is worth it on a 2Mbps link.

Roland Acra
Cisco Systems, Europe