OC12 vs Gigabit ethernet

[dong-lee]

Hi,

We currently have OC12 connection in our network, and we are thinking of replacing OC12 with Gigabit ethernet connection.

Is there any drawback switching OC12 to gigabit ethernet connection?

Would gigabit ethernet connection perform well as OC12?

Thank you in advance.

[smif101]

I think the question you need to ask yourself is the OC-12 not performing for you. I would have to assume that it is and that it is not overutilized. I haven't used a GigE connection as a WAN link but I am sure that it is fine. I personally would not go that way though, especially if the OC-12 has no problems. If it isn't broke don't fix it, however if the company could save considerable money using the ethernet connection than that would be the only reason for doing the upgrade.

[dong-lee]

Thanks for your writing.. :)

I wasn't sure how is it to have a GigE as a WAN link since I don't really have any experience with it either.

We don't have any problem with current OC12 connection, however, ISP offered the GigE solution considerably cheaper than OC12. Cheaper solution and faster link sounded like the winner... :)

Thank you

[santacorp]

Gigabit ethernet will perform pretty well. However it all depends on what kind of traffic you are carrying. Typically data and video traffic have been doing pretty well with GigE. In case of voice also when using VoIP voice also has been good. Only think I have observed in my experience is that the jitter variation is higher in gigE but the upper protocols take care of any side effects. You should be better and start benifiting the price break :)

[dong-lee]

Hi,

It's interesting that you mentioned about jitter variation. Could you please explain more in detail?

I'm trying to be prepared... :)

Thank you

[santacorp]

Hi,

I am not MPEG fluent, but will try to explain the issue which was caused by jitter variation.

While deploying a video stream from a cable head-end to a downstream hub location, the MPEG receiver was having frame sync issues. I guess it was unable to sync to the I-frames. The jitter variations was causing this. Previously this path had a SONET link and never had such issues. However while encoding the video stream by encoding the I-frames more often which in turn reduces the compression levels avoided this issue. This allowed the MPEG receiver to better sync up with the changes in the video frames.

Please note that apart from GigE based transport there are products that do Optical-Ethernet which do not look at each ethernet frame hence avoid some of these disadvantages. These optical-ethernet technologies are asynchronous in nature but have lower costs as they utilize the ethernet technology chipsets.

Best of Luck.