[RPRWG] The potential RPR market

["Harmen van As" <Harmen.R.van-As@xxxxxxxxxxxx>]

Dear Sanjay

 

I am not worried about delays on super-high speed backbone and regional rings. Here I agree, there is not much to gain by implementing preemption. I am addressing a much and much larger market than telecommunication backbone and regional rings. That market comprises rings and backbone rings for small offices, hotels, major stores, small business centers, hospitals, companies, campus areas, manufactury plants, industrial plants, small public access areas, ships, airplaines, cars, interconnection of base stations of wireless networks, etc., etc.

 

The motivation to install RPR in that market will be resilience and QoS. That market needs also lower speeds rings,  for instance also 100 Mbit/s Ethernet and 155 Mbit/s SONET/SDH or other transmission links in that speed range. If IEEE 802.17 also gains that market, it will be extreme successful. A huge market for the telecomunnication, data and chip industries. I cannot imagine that including the lower speed range would seriously delay the completion of the standard, when there is a group of members that is interested to work out the corresponding details. To my opnion, IEEE 802.17 has nothing to loose by extending the application areas of RPRs.

 

The standard could for instance define that on rings in this lower speed range preemption is allowed and that products with and without preemption as well as cut-through and store-and-forward operations must interwork. On higher speed rings, there is no preemption and here products using cut-through or store-and-forward must operate together.

 

Best regards

Harmen

----- Original Message -----

From: Sanjay Agrawal

To: 'Harmen van As' ; stds-802-17@xxxxxxxx

Sent: Friday, April 13, 2001 5:29 AM

Subject: RE: [RPRWG] Additional comments on preemption, cut-through and store-and-forward

Jumbo frames which are only 9K at 10 Gig will only give you 7.2 micrsecond delay/per node. With 32 nodes this is only 230.4 Microsecond delay.

 

at 2.5 gig it is approximately 1Ms

 

at 40Gig it is only 57 microseconds.

 

For 100msec latency budget, with 50msec consumed by the circumfrence of earth, we still got 50ms of switching latency. What is a big deal in saving few micro seconds in RPR rings. 

 

Real latency we should consider is the queueing latency in rest of the network for voice applications. Class based queueing

with voice class scheduled first is the solution.

 

 

-Sanjay