Hello
Van Jacobson TCP/IP Header Compression in ppp profiles is not supported on CCR1072-1G-8S+ ?
Which platforms support vj-compression?
ROS 6.44
Best regards
I think none of them do.
This protol was devised (and had its place) in the days when IP was used over slow serial links (async lines and modems).
I don’t think it is much used today.
Now, there is another compression option in PPP. That should compress entire packets using algorithms like LZW.
However, I think it does not work either. (you can enable them but I have never seen them actually do anything)
That is also quite typical in PPP implementations today.
Yeah i know that is old protocol and it was supported on ROS until 6.30 i think… i do some research and testing compresion on ppp for some project.. i have tried turn on headers and payload commpresion on IP->Packing but with no results like turn compresion on ppp profile..
I have tried to compress traffic from 3.4Mbps over tunell to 3.0-3,1 like traffic without “big” tunnel headers and etc..
Thx
Of course it depends on your payload traffic if compression is going to work at all.
VJ compression works only when a single TCP stream is running over the link. It was invented for the typical case of a
single user operating a terminal over a slow modem connection to make telnet connection to a single server.
In that case it can do a lot. When joining two networks with several connections running in parallel, it cannot do so much.
LZW compression only works when data is compressible. Now that could work well on uncompressed HTML traffic, but
today this is usually sent encrypted and/or there already is content-compression. Then LZW compression won’t do anything.
This fact-of-life also makes manufacturers support compression ever less. When it causes headaches, costs CPU performance,
and does not bring any gain, way even attempt it?
That said, did you ever detect that PPP compression was working? Between two MikroTiks or also between MikroTik and
another router or client manufacturer?
It is difficult to check because there isn’t even a status field that shows if compression was negotiated and what the average
compression ratio is… I think it just doesn’t work.
Thanks for the detailed explanation.
Yes i send uncompressible traffic thru the tunnel..
Make sanse all now when you explain how LZW commpresion works.
I did not eaven know/investigate what kind of commpresion/alghoritam ros use for that purpose.
Thx
Yeah in that case there won’t be any compression. The only thing that could be reduced is the repeated IP and Tunnel headers,
that is kind of what VJ compression was about, but it only handled single-session TCP/IP, not the generic case.
So I think compression is not going to help you, you will either need more bandwith or less traffic.
Yes… according on bandwith in ip firewall connections on single tcp ip connections have no mbps differences when use-commpression=yes in my case.. i mean in case on reduced headers.
LZW compression does not do much for header compression. It mainly compresses repeated characters or text in the body.
So lots of spaces, or lots of
or or similar strings would be compressed.
But not headers or encrypted or already compressed data, because it does not contain such repeated characters or strings anymore.
Thx for infos 
Best regards