Hi,
Those not specified by the router are either routed by the server or produce IPX
protol errors and are dropped.
It is important not to have the various frame types set on the servers or service
advertisers. If for example you are normally using Novell-Ether (802.3) and you put
in a server using Netware 4.x running SAP (802.2). Now when you put in the first
server you configure both the SAP and Novell Ether in the server. You have 802.3
(Novell-ether) configured in the router. Pull out the original server and you have no
network. Othen you will lose half of your local clients.
Have lose networks and or frame types can also create some horrible little routing
loops and unwanted traffic. SAP's, RIP updates etc.
Let the router route and servers serve.
Another one that sometimes grabs you.
Teunis,
Hobart, Tasmania
Australia
On Tuesday, February 06, 2001 at 08:45:48 AM, Leigh Anne Chisholm wrote:
> John,
>
> What's the purpose of a default frame type? In IPX? What does the router
> do with other frame types not specified?
>
> Now what about with IP? What's the purpose of the default frame type? What
> does the router do with other frame types not explicitly specified?
>
>
> -- Leigh Anne
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> Priscilla Oppenheimer
> Sent: February 5, 2001 2:03 PM
> To: John Neiberger; [EMAIL PROTECTED]
> Subject: Re: Another 802.3 and Ethernet Question
>
>
> At 07:38 AM 2/5/01, John Neiberger wrote:
> >While studying for CIT, I noticed something that had never occurred to me
> >before. The default ethernet frame type on a Cisco router is Ethernet_II,
>
> The default frame type depends on the payload.
>
> The default for IP is Ethernet V2 because the IP industry never adopted
> anything newer at the data-link layer. (They did adopt new physical-layer
> IEEE 802.3 standards.) Ethernet V2 has dest, source, and EtherType. If you
> were to change the frame type on the routers, you would have to change it
> on all IP hosts too, which would be a pain. Most operating systems (Windows
> 9x, Window NT, SunOS, Mac OS, etc.) default to Ethernet V2 for IP also.
>
> If you use AppleTalk Phase 2, the default frame type is 802.3 with 802.2
> and SNAP. That's because all Macintoshes and other AppleTalk devices
> default to that frame type for AppleTalk also. (Phase 1 was Ethernet V2, by
> the way.)
>
> If you use Novell, the default is Novell "raw," aka Ethernet_802.3 which
> has dest, source, length, immediately followed by the IPX header which
> starts with an XNS checksum, which isn't used so it's always FFFF.
>
> The Novell default may have changed. I know Novell has been wanting to get
> with the rest of the world, plus they have been talking about actually
> using the checksum, which means they can't use the raw format. Also the raw
> format is kind of ugly because a "raw" frame arrives at a station
> configured for 802.3 with 802.2, the FFFF looks like a global LLC (802.2)
> SAP, which means "give this frame to all services!.
>
> Priscilla
>
> >but the only physical interface specified by Ethernet version 2 is 50-ohm
> >coax, IIRC, similar to 10base5 On 10baseT or 100baseTX interfaces, which
> >are on every router I've ever worked with, why is the default frame type
> not
> >IEEE 802.3?
> >
> >Ethernet_II only has a type field, while IEEE 802.3 frames include 802.2
> >information. What sorts of functionality would be available through the
> use
> >of that frame type that are not available with Ethernet_II?
> >
> >In IP-only environments, would there be a good reason to change to a
> >different frame type, or would we only benefit from a different frame type
> >in a non-IP environment or mixed environment?
> >
> >Thanks,
> >John
> >
> >
> >
> >
> >
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> ________________________
>
> Priscilla Oppenheimer
> http://www.priscilla.com
>
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