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dljvjbsl
dljvjbsl
12/5/2012 | 1:49:17 AM
re: Siemens Sees Ethernet Everywhere

I would add that no effective LAN technology was developed (DQDB was a faint attempt), while Ethernet progressed with star topology and wider bandwidth capacity


Wouldn't DQDB abd Orwell (especially ORwell if I rememeber correctly) be considered the direct forbearers of RPR. Both of their MAC layers, as I recall them from so many years ago, would not be out of place as Ethernet variants.
PO
PO
12/5/2012 | 1:49:16 AM
re: Siemens Sees Ethernet Everywhere
Wouldn't DQDB abd Orwell (especially ORwell if I rememeber correctly) be considered the direct forbearers of RPR.

Interesting comment. I certainly can't speak for other efforts which contributed to the creation of RPR, but in the effort I participated in we weren't looking at these per se.

Personally, I had a sort of a "Token Ring Ethernet" in mind, where stations were not restricted to a single token on the ring, but simply had transmission rules based on local and thru traffic (bidirectionally).
iometro
iometro
12/5/2012 | 1:49:15 AM
re: Siemens Sees Ethernet Everywhere
Wouldn't DQDB abd Orwell (especially ORwell if I rememeber correctly) be considered the direct forbearers of RPR.

If I am correct, RPR was also decended from DTM, a standard that is almost as doomed as its biggest cheerleader (the Swedish company formerly known as Dynarc).
sgan201
sgan201
12/5/2012 | 1:49:14 AM
re: Siemens Sees Ethernet Everywhere
Hi sevenbrooks,
Do you consider for each user having a single VCC that goes from DSLAM all the way to the BRAS (by the way, both of them are not on the same CO) that run that ATM COS of better than UBR, ATM QOS or not ATM QOS?? And, because the ATM COS that you receive for the DSL modem is non-UBR, it is guaranteed even during network congestion..

Then, you could have done priority queueing on this single VCC that has guaranteed bandwidth..

Dreamer
sevenbrooks
sevenbrooks
12/5/2012 | 1:49:12 AM
re: Siemens Sees Ethernet Everywhere

Dreamer,

Sorry nobody is setting up CBR for residential users. Right now average backbone is 15 kb/s per sub not 1.5 Mbs per sub so it don't work.

VBR is too complicated to set up. Too many intermitent problems. Works today but not tommorow. If it is an intermitent service than nobody is going to pay for it. Also again, we have to up the backbones.

So, no it does not work. ATM QoS works fine within its domain. However, the 2 QoS domains are ignorant of each other therefore they can not cooperate.

Video over DSL works by defining two VCCs. One for CBR traffic (video streams) and one for UBR traffic (control channels and user data. Even then the traffic requires the local ethernet in the home to have QoS support with the video taking precedence.

seven
PO
PO
12/5/2012 | 1:49:11 AM
re: Siemens Sees Ethernet Everywhere
My understanding is that RPR was actually inspired by FDDI. Yes, it morphed a bit, but...


Once again, at the Major Industry Participant for whom I worked at the time, this was never a thought. I can't speak for Cisco, Lantern, etc.

I do find it curious to see how others (who had no idea what was happening at the time) choose to portray what happened at the time ... just as I found it interesting trying to fight individiuals who didn't 'get it' at the time.
Tony Li
Tony Li
12/5/2012 | 1:49:11 AM
re: Siemens Sees Ethernet Everywhere
My understanding is that RPR was actually inspired by FDDI. Yes, it morphed a bit, but...

Tony
sgan201
sgan201
12/5/2012 | 1:49:10 AM
re: Siemens Sees Ethernet Everywhere
Hi seven,
DSL service is on VBR. It is not on CBR or UBR.

Dreamer



sigint
sigint
12/5/2012 | 1:49:09 AM
re: Siemens Sees Ethernet Everywhere
Tony:
You can have QoS on an Ethernet just like any other point to point media. Just don't use an under-buffered switch that doesn't recognize your QoS identification and there is no issue.
__________________________________________________
Hi Tony,
Any pointers to appropriate buffer sizing? I guess too much doesn't help (hold on to a packet too long and there would be re-transmission), plus, it adds to latency. Most merchant silicon uses solely ingress buffering, leaving the device susceptible to HOL blocking.

What's your opinion on cut-through architectures vis-a-vis store-and-forward?

Thanks,
Sigint
sevenbrooks
sevenbrooks
12/5/2012 | 1:49:08 AM
re: Siemens Sees Ethernet Everywhere

Hi Dream,

I make DSLAMs. All are on UBR. Nobody even requires support of VBR.

seven
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