[X4U] Cable modem vs router

[David Ledger]

>From: Jonnythan <jonnythanster at googlemail.com>
>I'm having a problem getting my cable modem to work at full speed via my
>router. My speed is twice as good when I go straight from the modem to the
>Mac's built-in ethernet (Dual 2.7 GHz PowerPC G5, OS X 10.4.9).
>I thought the problem might be the age of the router, but buying a new one
>only improved the situation slightly. I need a router to link up with
>another Mac and a networked printer, but it isn't essential that I get
>internet access for anything else.
>I was wondering whether it would be a good plan to install an ethernet card
>and run the cable modem directly from that, whilst leaving the router
>connected to the built-in ethernet? Does anyone have any idea whether that
>would work and be as good as running from the built-in ethernet?
>Or is there anything else available that might help e.g. some sort of
>adapter to plug two devices into the built-in ethernet (i.e. a sort of
>router without any of a router's impedence)?

What makes / models are the old & new routers?

A basic 100Mbps router should be faster than any domestic network 
feed. There must be some incompatible setting between either the 
Router and the Modem or the Mac and the Router that's causing stuff 
to be fully stored and forwarded rather than passed along only 
slightly delayed. If the Router has a Firewall and it's set up, each 
packet will have to be compared to its tables before passing it on. 
The overhead for NAT (Network Address Translation, which the Router 
will be doing) is small. The things to look out for are Full/Half 
Duplex (which I havn't seen a setting for) and MTU, which is the 
maximum packet length. If the Modem is using packets longer that 
1500, then the Mac will handle it, but the Router might need a 
setting changed else each packet will have to be split and 
reconstructed.

David


-- 
David Ledger - Freelance Unix Sysadmin in the UK.
HP-UX specialist of hpUG technical user group (www.hpug.org.uk)
david.ledger at ivdcs.co.uk
www.ivdcs.co.uk