«

Hello.

We had a test lab set up with three 2621XM routers off of two of the
routers are ASEtesters connected via serial to nm-16a.

This is to simulate a RTU (remote terminal Unit) in the field (slave)
and the master RTU. The three routers are connected in a triangle
(mesh) with serial to serial configured at (as) a T1.


Router B
. .
. .
. .
. .
master---------Router A................Router C--------SlaveASE (RTU)
ASE (RTU)

What happens is that the master RTU polls the slave RTU. a reverse
telnet connection between Router C and Router A is established and the
data is sent. However a problem arises,,, if during the exchange we
break the connection between Router A and Router C, Router A doesnt
continue to get the information.



Router B
. .
. .
. .
. .
master---------Router A.. open ....Router C--------SlaveASE (RTU)
ASE (RTU)

What we think is happening is that when the reverse telnet session is
opened it is going to the IP on Router A serial interface and it is
working fine. However when the connection between Router A and Router
C is broken it reroutes to Router B but still has the destination of
Router A serial interface (the one looking at C) as its destination
and the sessions won't continue.

We want to have the session open to Router As loopback IP, that way we
feel that when the connection between A&C is broken the loopback IP on
A will sill be up.

How do I do this? Or does anyone have any other ideas? We will also
look into using UDP instead of TCP and hence UDPTN.

Thanks
Alan Andrews

1. Configure a loopback0 interface on all 3 routers.
2. Be sure that you have configured routing such that,
if any one of A,B,C is down, the remaining 2 routers
will each still have reachability to the other's loopback0
3. When establishing a TCP connect between any of A,B,C,
always use the syntax

telnet w.x.y.z <port> [/stream] /source-interface loopback 0

async tunneling advice:

http://www.cisco.com/warp/public/700/14.shtml

Aaron

---

~ Hello.
~
~ We had a test lab set up with three 2621XM routers off of two of the
~ routers are ASEtesters connected via serial to nm-16a.
~
~ This is to simulate a RTU (remote terminal Unit) in the field (slave)
~ and the master RTU. The three routers are connected in a triangle
~ (mesh) with serial to serial configured at (as) a T1.
~
~
~ Router B
~ . .
~ . .
~ . .
~ . .
~ master---------Router A................Router C--------SlaveASE (RTU)
~ ASE (RTU)
~
~ What happens is that the master RTU polls the slave RTU. a reverse
~ telnet connection between Router C and Router A is established and the
~ data is sent. However a problem arises,,, if during the exchange we
~ break the connection between Router A and Router C, Router A doesnt
~ continue to get the information.
~
~
~
~ Router B
~ . .
~ . .
~ . .
~ . .
~ master---------Router A.. open ....Router C--------SlaveASE (RTU)
~ ASE (RTU)
~
~ What we think is happening is that when the reverse telnet session is
~ opened it is going to the IP on Router A serial interface and it is
~ working fine. However when the connection between Router A and Router
~ C is broken it reroutes to Router B but still has the destination of
~ Router A serial interface (the one looking at C) as its destination
~ and the sessions won't continue.
~
~ We want to have the session open to Router As loopback IP, that way we
~ feel that when the connection between A&C is broken the loopback IP on
~ A will sill be up.
~
~ How do I do this? Or does anyone have any other ideas? We will also
~ look into using UDP instead of TCP and hence UDPTN.
~
~ Thanks
~ Alan Andrews

Aaron

Great, Ill give it a try.
I didnt think of "/source-interface loopback 0
"

May just do it.

Also, the master polls the slave and them the connection fails, what
can I do to have the reverse telnet session terminate. I am thinking
that the network reconverges and if a new session were to be initiated
it would use the new path. The origional sessions isnt ending.



Aaron Leonard <> wrote in message news:<>. ..
> 1. Configure a loopback0 interface on all 3 routers.
> 2. Be sure that you have configured routing such that,
> if any one of A,B,C is down, the remaining 2 routers
> will each still have reachability to the other's loopback0
> 3. When establishing a TCP connect between any of A,B,C,
> always use the syntax
>
> telnet w.x.y.z <port> [/stream] /source-interface loopback 0
>
> async tunneling advice:
>
> http://www.cisco.com/warp/public/700/14.shtml
>
> Aaron
>
> ---
>
> ~ Hello.
> ~
> ~ We had a test lab set up with three 2621XM routers off of two of the
> ~ routers are ASEtesters connected via serial to nm-16a.
> ~
> ~ This is to simulate a RTU (remote terminal Unit) in the field (slave)
> ~ and the master RTU. The three routers are connected in a triangle
> ~ (mesh) with serial to serial configured at (as) a T1.
> ~
> ~
> ~ Router B
> ~ . .
> ~ . .
> ~ . .
> ~ . .
> ~ master---------Router A................Router C--------SlaveASE (RTU)
> ~ ASE (RTU)
> ~
> ~ What happens is that the master RTU polls the slave RTU. a reverse
> ~ telnet connection between Router C and Router A is established and the
> ~ data is sent. However a problem arises,,, if during the exchange we
> ~ break the connection between Router A and Router C, Router A doesnt
> ~ continue to get the information.
> ~
> ~
> ~
> ~ Router B
> ~ . .
> ~ . .
> ~ . .
> ~ . .
> ~ master---------Router A.. open ....Router C--------SlaveASE (RTU)
> ~ ASE (RTU)
> ~
> ~ What we think is happening is that when the reverse telnet session is
> ~ opened it is going to the IP on Router A serial interface and it is
> ~ working fine. However when the connection between Router A and Router
> ~ C is broken it reroutes to Router B but still has the destination of
> ~ Router A serial interface (the one looking at C) as its destination
> ~ and the sessions won't continue.
> ~
> ~ We want to have the session open to Router As loopback IP, that way we
> ~ feel that when the connection between A&C is broken the loopback IP on
> ~ A will sill be up.
> ~
> ~ How do I do this? Or does anyone have any other ideas? We will also
> ~ look into using UDP instead of TCP and hence UDPTN.
> ~
> ~ Thanks
> ~ Alan Andrews

On 20 Jan 2004 04:44:35 -0800, (A. Andrews) wrote:

~ Aaron
~
~ Great, Ill give it a try.
~ I didnt think of "/source-interface loopback 0
~ "
~
~ May just do it.
~
~ Also, the master polls the slave and them the connection fails, what
~ can I do to have the reverse telnet session terminate.

Turn on TCP keepalives on all sides.

Aaron

-----

~ I am thinking
~ that the network reconverges and if a new session were to be initiated
~ it would use the new path. The origional sessions isnt ending.
~
~
~
~ Aaron Leonard <> wrote in message news:<>. ..
~ > 1. Configure a loopback0 interface on all 3 routers.
~ > 2. Be sure that you have configured routing such that,
~ > if any one of A,B,C is down, the remaining 2 routers
~ > will each still have reachability to the other's loopback0
~ > 3. When establishing a TCP connect between any of A,B,C,
~ > always use the syntax
~ >
~ > telnet w.x.y.z <port> [/stream] /source-interface loopback 0
~ >
~ > async tunneling advice:
~ >
~ > http://www.cisco.com/warp/public/700/14.shtml
~ >
~ > Aaron
~ >
~ > ---
~ >
~ > ~ Hello.
~ > ~
~ > ~ We had a test lab set up with three 2621XM routers off of two of the
~ > ~ routers are ASEtesters connected via serial to nm-16a.
~ > ~
~ > ~ This is to simulate a RTU (remote terminal Unit) in the field (slave)
~ > ~ and the master RTU. The three routers are connected in a triangle
~ > ~ (mesh) with serial to serial configured at (as) a T1.
~ > ~
~ > ~
~ > ~ Router B
~ > ~ . .
~ > ~ . .
~ > ~ . .
~ > ~ . .
~ > ~ master---------Router A................Router C--------SlaveASE (RTU)
~ > ~ ASE (RTU)
~ > ~
~ > ~ What happens is that the master RTU polls the slave RTU. a reverse
~ > ~ telnet connection between Router C and Router A is established and the
~ > ~ data is sent. However a problem arises,,, if during the exchange we
~ > ~ break the connection between Router A and Router C, Router A doesnt
~ > ~ continue to get the information.
~ > ~
~ > ~
~ > ~
~ > ~ Router B
~ > ~ . .
~ > ~ . .
~ > ~ . .
~ > ~ . .
~ > ~ master---------Router A.. open ....Router C--------SlaveASE (RTU)
~ > ~ ASE (RTU)
~ > ~
~ > ~ What we think is happening is that when the reverse telnet session is
~ > ~ opened it is going to the IP on Router A serial interface and it is
~ > ~ working fine. However when the connection between Router A and Router
~ > ~ C is broken it reroutes to Router B but still has the destination of
~ > ~ Router A serial interface (the one looking at C) as its destination
~ > ~ and the sessions won't continue.
~ > ~
~ > ~ We want to have the session open to Router As loopback IP, that way we
~ > ~ feel that when the connection between A&C is broken the loopback IP on
~ > ~ A will sill be up.
~ > ~
~ > ~ How do I do this? Or does anyone have any other ideas? We will also
~ > ~ look into using UDP instead of TCP and hence UDPTN.
~ > ~
~ > ~ Thanks
~ > ~ Alan Andrews

In article < >,
says...
> Aaron
>
> Great, Ill give it a try.
> I didnt think of "/source-interface loopback 0
> "
>
> May just do it.
>
> Also, the master polls the slave and them the connection fails, what
> can I do to have the reverse telnet session terminate. I am thinking
> that the network reconverges and if a new session were to be initiated
> it would use the new path. The origional sessions isnt ending.


service tcp-keepalives

Or something like that....to turn on tcp keepalives.


--

hsb

"Somehow I imagined this experience would be more rewarding" Calvin
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