& cplSiteName &
Comments
Newest First  |  Oldest First  |  Threaded View        ADD A COMMENT
<<   <   Page 5 / 12   >   >>
pig3head
pig3head
12/5/2012 | 1:50:29 AM
re: Siemens Sees Ethernet Everywhere
I have friends that do VoIP and online gaming.. Those two applications are the one that force them to change over from cable modem to DSL.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
usually, serveral cable modem aceess end-users share a uplink which runs at the rate about 20Mbps, which can support few users.

i am sure DSL will beat cable modem access and not sure which of FTTP and xDsl will win the last war,in the situation that 2 guys announced VDSL reaching rate at 100Mbps.
pig3head
pig3head
12/5/2012 | 1:50:29 AM
re: Siemens Sees Ethernet Everywhere
I couldn't possibly agree more with that statement.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

would you accept TVoDsl and VoIp without Qos after paying additional charge for value added service?

i work for one which makes pure ip-dslam.

we terminate the atm at the access line card and have to map its PVC to vlan-id to add a 802.1q tag to the ethernet frame before the frame entering the switch fabric to achive a 802.1p DiffServ model QOS capacity.

A similar step deals with the returned ethernet frame before it leaving the line card.

All there tag adding and deleting stages are done just for achiving Qos capacity for ipdslam to support value added service.

Qosless dslam has not ability to play with future triple-play game.
Tony Li
Tony Li
12/5/2012 | 1:50:22 AM
re: Siemens Sees Ethernet Everywhere
Won't having to run packet trunk at average 60% or lower utilization to avoid queueing delay a even bigger problem??

This is one of the biggest lie and fallacy that have been going on for at least 10 years. Until and unless one of the IP guru show up and tell the truth, I have very little regard for the IP folks' capability to tell the truth..
-----------

Dreamer,

As has been pointed out, the links that we're talking about are point-to-point Ethernets, that are, effectively being used as serial lines with a funny encapsulation. Queueing delays that result from a collision domain are no longer applicable as soon as you went full-duplex.

Further, if you care about queueing delay, you might want to consider enabling QoS. Once enabled, you can run that trunk as hot as you like and drop that annoying best effort traffic.

Tony
Tony Li
Tony Li
12/5/2012 | 1:50:21 AM
re: Siemens Sees Ethernet Everywhere
tony said that:
The issue about cell overhead is on the wire, not internal to the system.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
what does this means?

for ATM cell, 5 overhead bytes is added for atm routing&Qos before the 53bytes cell leaving the SAR to enter the wire.
this 5 bytes do be overhead of atm internal system.
-----------------------


If you want to argue about the efficiencies of cells, you have to take the cost of inefficiency into account. If you want to send a cell across an electrical backplane, you need to provision a certain amount of excess capacity on that backplane. This is relatively cheap. If you want to send a cell across a LH network, then you have to provision that extra inefficiency in LH bandwidth. That's expensive.

Cells are agnostic. They have advantages and disadvantages. Folks who have a religion and don't evalute technology on its true merits are condemmed to preach forever.

Tony
Tony Li
Tony Li
12/5/2012 | 1:50:20 AM
re: Siemens Sees Ethernet Everywhere
mass market = residential access

----------

Sorry, no. The mass market for networking gear is the Enterprise. The internal bandwidth of an office building frequently is several orders of magnitude more than its external bandwidth. Similarly, the number of Ethernet ports sold into Enterprises far exceeds the sum total of all ports bought by carriers for core, access and aggregation combined.

As with all things silicon, costs are driven by volume. The Enterprise chose Ethernet (no matter what the real technology is, we'll call it Ethernet ;-), and that drives the volume and that drives CoGS and in turn end user prices.

As soon as you do something outside the volume envelope, your costs go way up. That little phrase "carrier grade" is a 10x price multiplier.

Tony
sigint
sigint
12/5/2012 | 1:50:16 AM
re: Siemens Sees Ethernet Everywhere
Tony:
If you want to argue about the efficiencies of cells, you have to take the cost of inefficiency into account.
_________________________________________________

Tony,

Aside from the bandwidth, won't fixed cell size entail additional processing for packet scatter-gather (and the attendant hit on throughput)?

thanks,
Sigint
Tony Li
Tony Li
12/5/2012 | 1:50:16 AM
re: Siemens Sees Ethernet Everywhere
Yes, but transistors are cheap.

Tony
sgan201
sgan201
12/5/2012 | 1:50:15 AM
re: Siemens Sees Ethernet Everywhere
Hi,
VoIP run at 90Kbps or less.. Current online games need only about 128Kbps. Bandwidth is not the issue.. QOS is. Jitter and packet loss is the problem.

Payback is hell!!! I will enjoy my days in the sun seeing all these all these converged application expose the QOS problem of all these Ethernet everywhere design..

A person can tell whether his VoIP phone call works well or not. He/she does not need a Phd to know that. Ditto for online gaming.

"The truth will set you free!!!"

Dreamer

mr zippy
mr zippy
12/5/2012 | 1:50:13 AM
re: Siemens Sees Ethernet Everywhere
I think you'll find that a lot of problems with latency sensitive applications on DSL and Cable networks is due to the bandwidth asymmetry of the links.

It is worth having a browse through the following RFC, which discusses this issue.

"TCP Performance Implications of Network Path Asymmetry"
http://www.faqs.org/rfcs/rfc34...

jepovic
jepovic
12/5/2012 | 1:50:12 AM
re: Siemens Sees Ethernet Everywhere
Two things:
* Ethernet in the first mile (from CPE to DSLAM) will take much longer than Ethernet in the second mile (from DSLAM to IP edge), because that requires new CPEs. Ethernet in the first mile doesn't bring much cost savings over the current ATM over DSL, since it's specific hardware anyhow (remember, enterprise LANs use CAT 5 cables, not telephone copper cables)
* Ethernet switches have sufficient QoS for VoIP, gaming and everything you like except leased line-type quality. Same thing with the Ethernet/IP DSLAMs (IP DSLAM is a ridiculous name!). Anyway, Ethernet is mostly used point to point, and the QoS is really on the IP layer, as Tony Li pointed out.

ATM is really like Token Ring. In principle it's a fine technology, but in reality it doesn't stand a chance against Ethernet's economies of scale. People holding on to ATM now are like the people holding on to Token Ring 15 years ago.

Operators are not as technology-dependent as vendors, and not as sentimental. Protocols come and go all the time, as they always have. X21, X25, ISDN etc have all had their heydays. Right now, the whole industry is focusing on IP, MPLS and Ethernet. Even if I as an operator would prefer another protocol, it will be too expensive to stay out of the mainstream of technical development.
<<   <   Page 5 / 12   >   >>


Featured Video
Upcoming Live Events
November 5, 2019, London, England
November 7, 2019, London, UK
November 14, 2019, Maritim Hotel, Berlin
December 3-5, 2019, Vienna, Austria
December 3, 2019, New York, New York
March 16-18, 2020, Embassy Suites, Denver, Colorado
May 18-20, 2020, Irving Convention Center, Dallas, TX
All Upcoming Live Events