[Xorp-users] Emulating multiple routers on the same host

[Atanu Ghosh]

Hi,

I have recently been experimenting with imunes
<http://www.imunes.net/>. Imunes allows the creation of multiple network
stacks on a single host. Currently Imunes only works on FreeBSD 4.11 and
requires kernel modifications. I have built a FreeBSD 4.11 system inside
vmware applied the kernel patches and built XORP. My very limited
experiments have worked well. Multiple instances of XORP can be run on a
single host each on its own network stack. Therefore no modifications to
XORP.

If you want to run multiple instance of XORP/BGP on one host the
instructions are below.

NOTE: BGP IS THE ONLY PROTOCOL THAT CAN BE RUN THIS WAY.

	 Atanu.
========================================

1) Modify the template files to run the dummy fea rather than the real
fea. Otherwise multiple processes will attempt to modify the routing
table. In xorp/etc/templates run the script below or modify the
templates manually.

----------------------------------------
#!/bin/sh

grep -l \"fea/xorp_fea\" * |
while read name
do
   echo $name
   ed $name <<\!
1,$s/"fea\/xorp_fea"/"fea\/xorp_fea_dummy"/
wq
!
done
----------------------------------------

2) Create the router configuration files. The BGP protocol requires
that port 179 is used TCP sessions. As our regression tests run on a
single host our BGP can be configured to use any port.

Below is the configuration for two XORP instances on a single host:

CONFIG1
----------------------------------------
interfaces {
    interface dc0 {
	vif dc0 {
	    disable: false
	    address 10.10.10.1 {
		prefix-length: 24
		broadcast: 10.10.10.255
		disable: false
	    }
	}
    }
}

protocols {
    bgp {
	bgp-id: 10.10.10.1
	local-as: 65001

	peer 127.0.0.1 {
	    local-ip: 127.0.0.1
	    as: 65002
	    next-hop: 10.10.10.1

	    local-port: 2001
	    peer-port: 2002
	}

	/* Introduce a route */
	network4 10.10.10.0/24 {
	    next-hop: 10.10.10.1
	    unicast: true
	    multicast: true
	}
	
    }
}
----------------------------------------

CONFIG2
----------------------------------------
interfaces {
    interface dc0 {
	vif dc0 {
	    disable: false
	    address 10.10.10.2 {
		prefix-length: 24
		broadcast: 10.10.10.255
		disable: false
	    }
	}
    }
}

protocols {
    bgp {
	bgp-id: 10.10.10.2
	local-as: 65002

	peer 127.0.0.1 {
	    local-ip: 127.0.0.1
	    as: 65001
	    next-hop: 10.10.10.2

	    local-port: 2002
	    peer-port: 2001

	}
    }
}
----------------------------------------

3) The different processes that make up a XORP router communicate with
each other using a default port. This port number can be changed using
the enviroment variable "XORP_FINDER_SERVER_PORT".

Start two instances of XORP in separate shells:
XORP_FINDER_SERVER_PORT=7001 ./xorp_rtrmgr -b CONFIG1
XORP_FINDER_SERVER_PORT=7002 ./xorp_rtrmgr -b CONFIG2

Either XORP router instance can now be communicated with by setting
the appropriate enviroment varaiable. Note that router2 has the route
introduced by router1.

----------------------------------------
emu$ XORP_FINDER_SERVER_PORT=7002 ./xorpsh
Welcome to XORP on emu.icir.org
Xorp> show bgp routes 
Status Codes: * valid route, > best route
Origin Codes: i IGP, e EGP, ? incomplete

   Prefix                Nexthop                    Peer            AS Path
   ------                -------                    ----            -------
*> 10.10.10.0/24         10.10.10.1                 10.10.10.1     65001 ?
Xorp> 
----------------------------------------
========================================

>>>>> "Ratul" == Ratul Mahajan <ratul@cs.washington.edu> writes:

    Ratul> James Courtier-Dutton wrote:
    >> On 8/1/05, Ratul Mahajan <ratul@cs.washington.edu> wrote:
    >> 
    >>> > You can currently run multiple BGP instances on the same
    >>> machine, as > BGP uses TCP, and you can configure the peer
    >>> address and port on a > per-peer basis.  So if you want to
    >>> experiment with BGP, this is > possible without code changes.
    >>> But the resulting virtual routers > won't actually forward
    >>> packets to each other, so this is only useful > for routing
    >>> experiments, not a general solution.
    >>> 
    >>> so whats the simplest way to accomplish this?
    >>> 
    >>> (i realize that the answer is there somewhere in the code/docs
    >>> but specific pointers would help.)
    >>  How about using XEN. You can then virtualise multiple Linux
    >> boxes efficiently, and run a single XORP on each one.

    Ratul> i guess that (and other interface-level virtualization
    Ratul> mechanisms) is an option but i'd be more interested in
    Ratul> retaining the configuration of the experimenting machine and
    Ratul> play at a user-level if possible.

    Ratul> thanks.  _______________________________________________
    Ratul> Xorp-users mailing list Xorp-users@xorp.org
    Ratul> http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/xorp-users