Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Author Topic: Broadcom Nitro ATM compression  (Read 2056 times)

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6565
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Broadcom Nitro ATM compression
« on: August 13, 2015, 06:16:56 PM »

Try as I might, I simply cannot find any description of how Broadcom’s ATM bytestream compression works.

From the very scant few mentions of its usage, I suspect it's completely throwing out all the ATM cells and just concatenating the payloads which gives it a best-case compression ratio of just below 48/53 (neglecting Broadcom's header and the ATM AAL5  trailer).

This is not to be sneezed at. Chipsets in the DSLAM and modem must both speak Nitro for it to work, whether or not it can auto-detect is unknown. If it could auto-detect, it might be deployable by BT and in that case could have a chance of taking over the world. (But if not, then the sales are 100% or zero.) If your modem can go ~10% faster than someone else’s then you have a killer advantage imo. Speed for free. Yum.

PS: I'm told that Sky use it. Can Sky LLU users use non-Sky CPE? That would answer the question.

(I wonder if there might be any way if adding an autodetect protocol on later? Hmm..)
« Last Edit: August 13, 2015, 06:27:08 PM by Weaver »
Logged

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6565
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: Broadcom Nitro ATM compression
« Reply #1 on: August 13, 2015, 07:02:10 PM »

Thanks to ejs
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31695
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: Broadcom Nitro ATM compression
« Reply #2 on: August 14, 2015, 12:26:43 AM »

Quote
PS: I'm told that Sky use it.

Do they though?   Apart from that one article (where its unconfirmed), there's no mention anywhere else and I don't think anyone has ever seen any evidence of it actually in use.

Quote
We’re still awaiting confirmation from Sky but we believe this can be employed by ISPs that use Broadcom’s DSLAM network devices inside telephone exchanges.

There seems to be little information about Nitro :(

Quote
Nitro is one of several competing incompatible proprietary extension approaches that were developed to increase performance of 802.11g wireless devices, such as 125 High Speed Mode from Broadcom,

There seems to be a French ISP who may have used it  - See Freenaute to be able to offer upto 28Mbps.
Although they mention the BCM6348 I cant seem to find any mention of it on the Broadcom site nor in the 6348 datasheet.  The only English reference I can really find is in relation to Broadcoms NitroQAM for wifi chips.

btw if it is proprietary, then like you say it would mean that both DSLAM and modem would have to be BCM.  Sky LLU MSANs are mostly Alcatels which irrc use BCM.  Although sky hubs for FTTC have BCM chipsets, I dont think all their adsl2+ routers do/did.

I can't see BTw as eager to use it because they have too many DSLAM/MSANs that arent BCMs..  plus unlike Sky they have absolutely no control at all over the type of modem/routers that are used by the EU.
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6565
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: Broadcom Nitro ATM compression
« Reply #3 on: August 14, 2015, 01:18:54 AM »

And Sky are going to have unhappy LLU customers if their non-Sky CPE, even though illegal, fails to work _at all_, unless there is a protocol auto-detect as mentioned eariler.
Logged

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6565
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: Broadcom Nitro ATM compression
« Reply #4 on: August 14, 2015, 01:24:04 AM »

Googling it produces pages of mentions from sites belonging to tester mfrs who say their testers speak Nitro. Cisco makes a box that speaks it. The Broadcom machine has managed to work on all those different mfrs to persuade them to care, unless of course its adoption requires no software in addition in, say, a tester, which I would be slightly surprised about, but it's certainly not impossible, unless I've missed something.
Logged