Subject: priorization of DLSW traffic

From: "Weiss, Richard VS T3" <[email-masked]>
Date: Wed, 23 Aug 95 15:11:00 PDT

Dear DLSw'ers,

my name is Richard Weiss and i'm working for Siemens AG, Germany. We are 
developing a branch multiplexer and planning to implement DLSw following RFC 
1795. Regarding to this i have some questions belonging to priorization.

1. From your experience, is it absolutely necessary to support different 
priorities at all?

2. Supposed we have queues of different priority: is it useful to let  DLSw 
use the  highest priority ( in a mixed configuration (e.g. SNA, NetBIOS and 
IP traffic))?
Can't this be a problem in case of a burst of SNA data (timeouts on the 
lower priority protocols?

3. Is a dynamically bandwidth management reserving a guaranteed bandwidth 
for DLSw traffic necessary at all (together with or alternatively to 
priorization) ?

4. In a multiprotocol configuration, do you have any estimations of how many 
percent of the total bandwidth of a WAN connection should be reserved for 
DLSw?

5. How can i imagine the interworking of protocol dependant priorization and 
the priorization mechanism inside of DLSw (exactly inside of the SSP 
messages).

6. Which problems do you see for being compatibe to other routers?

best regards,
     R. Weiss

 ---
Richard Weiss            Phone : 089/722-48117
Siemens AG, VS T313      Fax:  : 089/780-24678
81359 Muenchen           E-Mail: [email-masked]

---

From: [email-masked] (Donna Kidder)
Date: Tue, 29 Aug 1995 04:14:52 -0700

>1795. Regarding to this i have some questions belonging to priorization.

I didn't notice any other replies, so although my comments are late,
hopefully you will find them useful.
>1. From your experience, is it absolutely necessary to support different

Yes.  W/o it, you cannot control response time in multiprotocol environments.
>use the  highest priority ( in a mixed configuration (e.g. SNA, NetBIOS and

Ideally, the customer should have the ability to configure how they want
prioritiation to work.  If you do not have time to implement that in a
first release, putting SNA first is going to satisfy most customers.

NetBIOS is also DLSw'd.  If you prioritize DLSw, and do not distinguish the
two, and NetBIOS will likely hog the bandwidth.

>lower priority protocols?

Most other protocols (with the exception of NetBIOS) do not use DLC timers.
Higher layer timers (again, with the exception of NetBIOS) are generally
in the minute range instead of the second range.

You also need to determine how you service the queues.   Done properly, you
can avoid some of these problems.

>for DLSw traffic necessary at all (together with or alternatively to

It is another way to service the queues that prevents queue starvation.

>percent of the total bandwidth of a WAN connection should be reserved for

User dependent for either traffic or job-security reasons.  Best to allow
configuration.

>the priorization mechanism inside of DLSw (exactly inside of the SSP

This one didn't translate very well.  Can you say a different way?
>6. Which problems do you see for being compatibe to other routers?

We'll find out at the October connectathon.

>81359 Muenchen           E-Mail: [email-masked]

Donna S. Kidder
Product Manager, InterWorks Business Unit
Cisco Systems
7025 Kit Creek Road
PO Box 14987
Research Triangle Park, NC 27709
Phone:  919-472-2974,  Fax:  919-472-2986