Another Demand Dial Question...

  • Thread starter Thread starter Ali
  • Start date Start date
A

Ali

Hi again,
MS talks about routing protocols, and how they might keep a demand dial
connection up permanently if advertising interval is less than the idle time
out. so MS recommends not to run routing protocols over on-demand
connections. ok... seems nice... but how can we do it? right after this
topic there's a step by step on manually configuring static routes, but I
don't get it.(that is, I don't know if it is related to this specific topic
since it came right after it.) how do we filter out routing protocols from
'interested
traffic'? is the only thing needed to configure autostatic updates?

thanks a bunch,
Ali...


On-Demand Connections
The recommendation of static routing for on-demand demand-dial connections
is based on the fact that the routing protocols provided with the Windows
2000 Routing and Remote Access Service (Routing Information Protocol [RIP]
for IP, Open Shortest Path First [OSPF], RIP for IPX, Service Advertising
Protocol [SAP] for IPX) have a periodic advertising behavior that can cause
the connection to be made for each advertisement or to keep the connection
up permanently if the advertising interval is less than the idle time-out.
Due to the time, distance, and cost-sensitive nature of typical dial-up WAN
links, running routing protocols over on-demand connections is not
recommended.

Static routes for demand-dial routing are either manually configured or
automatically configured by using autostatic updates, discussed later in
this section.

Manual Configuration of Static Routes
Manual configuration of static routes is the adding of static routes that
are available across the demand-dial interface using the Routing and Remote
Access snap-in. For TCP/IP traffic, static IP routes must be added.

To add a static IP route that uses a demand-dial interface

1.. In the Routing and Remote Access snap-in, double-click IP Routing, and
then right-click Static routes.
2.. Select New, and then click Static route.
3.. In the Interface box, select the demand-dial interface.
4.. Type the appropriate values for Destination, Network mask, and Metric.
5.. If you do not want traffic for this static route to initiate the
demand-dial connection, clear the Use this route to initiate demand-dial
connections check box.
 
It depends how complex your setup is. If you only have one subnet at
either end, static routes are all you need. So if you want to connect a
172.16.0.0 network to a 192.168.1.0 network, you just need a static route
at either end to route traffic for the "other" subnet through the link. You
can set either end to dial on demand by checking the "use this route ... "
box .

Note that dial on demand is optional. You can initiate the connection
manually from either end or you can make it persistent. But you must have
the demand-dial interfaces. These are the symbolic names for the connection
(like a named interface) for associating the routes with the connection.
They also identify connections where there are options. For instance, if a
server can receive two or more router to router connections (such as from
branch offices), the calling router uses the demand-dial interface name (on
the answering router) as its username so that it connects to the correct
interface (and loads the correct route).

Autostatic updates are scripted routes which a router will send to a
requesting router on demand. They are not connected with dial on demand. The
link must already be up.

Ali said:
Hi again,
MS talks about routing protocols, and how they might keep a demand dial
connection up permanently if advertising interval is less than the idle time
out. so MS recommends not to run routing protocols over on-demand
connections. ok... seems nice... but how can we do it? right after this
topic there's a step by step on manually configuring static routes, but I
don't get it.(that is, I don't know if it is related to this specific topic
since it came right after it.) how do we filter out routing protocols from
'interested
traffic'? is the only thing needed to configure autostatic updates?

thanks a bunch,
Ali...


On-Demand Connections
The recommendation of static routing for on-demand demand-dial connections
is based on the fact that the routing protocols provided with the Windows
2000 Routing and Remote Access Service (Routing Information Protocol [RIP]
for IP, Open Shortest Path First [OSPF], RIP for IPX, Service Advertising
Protocol [SAP] for IPX) have a periodic advertising behavior that can cause
the connection to be made for each advertisement or to keep the connection
up permanently if the advertising interval is less than the idle time-out.
Due to the time, distance, and cost-sensitive nature of typical dial-up WAN
links, running routing protocols over on-demand connections is not
recommended.

Static routes for demand-dial routing are either manually configured or
automatically configured by using autostatic updates, discussed later in
this section.

Manual Configuration of Static Routes
Manual configuration of static routes is the adding of static routes that
are available across the demand-dial interface using the Routing and Remote
Access snap-in. For TCP/IP traffic, static IP routes must be added.

To add a static IP route that uses a demand-dial interface

1.. In the Routing and Remote Access snap-in, double-click IP Routing, and
then right-click Static routes.
2.. Select New, and then click Static route.
3.. In the Interface box, select the demand-dial interface.
4.. Type the appropriate values for Destination, Network mask, and Metric.
5.. If you do not want traffic for this static route to initiate the
demand-dial connection, clear the Use this route to initiate demand-dial
connections check box.
Click to expand...
 
Hi Bill, thanks for both replies.
though I'm still confused. let's say we have RIP in our network as the
routing protocol. Default interval for 'announcement's in 30 seconds. so if
these announcement's reach the router, they'll initiate a connection, and
keep it up since it keeps on sending 'data' every 30 secs. how can we
prevent this?

Regards,
Ali
 
I don't think it is a problem. I have never been in that situation, but
my understanding is that only TCP traffic will trigger dial on demand. UDP
won't do it.
 
A more common problem is that the demand-dial connection never drops.
Every time a packet goes over the connection, the timer is reset, so the
connection is never idle long enough to time out. This is why you need to
filter the traffic so that unwanted traffic doesn't keep the connection up.
 
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