[LARTC] Routing NDAS ?

[LARTC] Routing NDAS ?

[Andrew Lyon]

Hi,

I believe ndas devices (http://www.ximeta.com/web/technology/) use raw
Ethernet frames, as they require no tcp/ip configuration, the client
finds and authenticates with a code that is different for each device
sold, like a network mac address.

My pc is on a different segment to the ndas devices that we have, the
two segments are linked by a linux box that is doing routing and proxy
arp, can anybody suggest a way that I could access the ndas devices, I
can connect to a share on a server that is connected to one of the
devices, but that isn't very efficient :(

Andy




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Re: [LARTC] Routing NDAS ?

[Grant Taylor]

On 06/22/07 16:31, Andrew Lyon wrote:
> the two segments are linked by a linux box that is doing routing and 
> proxy arp,

Please bridge and do not use Proxy ARP.  Or if you really want to use 
Proxy ARP make sure that you are only Proxy ARPing for the MAC addresses 
of the NDAS device(s) and the client(s) that need to connect to it.

> can anybody suggest a way that I could access the ndas devices,

Set up a bridging router (a.k.a. brouter) to bridge all layer 2 traffic 
except for IP (and a few other select protocols) traffic.  You may only 
want to bridge traffic that is from the NDAS and or its client(s) and 
route the rest (DROP in the BROUTING chain of the broute table).



Grant. . . .
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RE: [LARTC] Routing NDAS ?

[Andrew Lyon]

>
>-----Original Message-----
>From: lartc-bounces@mailman.ds9a.nl
[mailto:lartc-bounces@mailman.ds9a.nl] >On Behalf Of Grant Taylor
>Sent: 22 June 2007 22:45
>To: Mail List - Linux Advanced Routing and Traffic Control
>Subject: Re: [LARTC] Routing NDAS ? 
>
>On 06/22/07 16:31, Andrew Lyon wrote:
>> the two segments are linked by a linux box that is doing routing and 
>> proxy arp,
>
>Please bridge and do not use Proxy ARP.  Or if you really want to use 
>Proxy ARP make sure that you are only Proxy ARPing for the MAC
addresses 
>of the NDAS device(s) and the client(s) that need to connect to it.

Are you saying that there is something wrong with proxy arp? So far it
works fine for us, we have 5 segments and approx 150 nodes.

Ndas devices don't work with proxy arp, bridge would, but at the moment
we are a 24/7 operation and making the necessary config changes for
bridge would be disruptive.

I will probably end up doing it, but I would like to know if there is
any alternative..

Andy

>> can anybody suggest a way that I could access the ndas devices,

>Set up a bridging router (a.k.a. brouter) to bridge all layer 2 traffic

>except for IP (and a few other select protocols) traffic.  You may only

>want to bridge traffic that is from the NDAS and or its client(s) and 
>route the rest (DROP in the BROUTING chain of the broute table).



Grant. . . .
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Re: [LARTC] Routing NDAS ?

[Grant Taylor]

On 6/22/2007 5:22 PM, Andrew Lyon wrote:
> Are you saying that there is something wrong with proxy arp? So far 
> it works fine for us, we have 5 segments and approx 150 nodes.

Is there something wrong with driving a stake in to the ground with a 
rock verses a sledge hammer, no.

I personally see no reason to ever use proxy arp when you can bridge.  I 
also see much finer grained control over bridging than I do of proxy 
arp.  Not to mention that with bridging, devices see the real MAC 
address verses the MAC of the device doing the proxy arp.

That being said, proxy arp has been around for more decades than 
bridging has.  I'm sure that there are situations where proxy arp is the 
better situation.  However personally I would have to have a situation 
where bridging would not work and proxy arp would for me to use proxy 
arp over bridging.  I guess some of this could be attributed to the fact 
that I have come in to networking with in the last 10 years and to me 
proxy arp is the old holdover about like NetBEUI is for some networks. 
(That is not to say that proxy arp has as many problems as NetBEUI does 
or vice versa.)

> Ndas devices don't work with proxy arp, bridge would, but at the 
> moment we are a 24/7 operation and making the necessary config 
> changes for bridge would be disruptive.

Do you have another system that you can put in to production that would 
connect to both broadcast domains and have it bridge just NDAS traffic 
and let your existing routers do what they are doing?  I can understand 
and appreciate the inability (technical / political / chronological) to 
be able to replace work on production systems.  That does not mean that 
you can not accomplish what is needed another way.

> I will probably end up doing it, but I would like to know if there is 
> any alternative..

Will adding a system just to bridge NDAS traffic work?



Grant. . . .
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