-----Original Message----- From: lartc-bounces@xxxxxxxxxxxxxxx [mailto:lartc-bounces@xxxxxxxxxxxxxxx] On Behalf Of ramsurrunv@xxxxxxxxxxxx Sent: Thursday, June 01, 2006 2:58 PM To: lartc@xxxxxxxxxxxxxxx Subject: Not understanding network setup!! > Hi to all, > > +-------+ eth1 +-------+ > | |==========| | > 'network 1' ----| A | | B |---- 'network 2' > | |==========| | > +-------+ eth2 +-------+ > > A and B are routers > > # tc qdisc add dev eth1 root teql0 > # tc qdisc add dev eth2 root teql0 > # ip link set dev teql0 up > > On router A: > > # ip addr add dev eth1 10.0.0.0/31 > # ip addr add dev eth2 10.0.0.2/31 > # ip addr add dev teql0 10.0.0.4/31 > > On router B: > > # ip addr add dev eth1 10.0.0.1/31 > # ip addr add dev eth2 10.0.0.3/31 > # ip addr add dev teql0 10.0.0.5/31 > > > The above has been quoted from LARTC HOWTO. I would like to know the > following things: > > 1) Are the 10.0.0.0/31, 10.0.0.2/31, 10.0.0.3/31...different networks? Are > the devices eth1, eth2 and teql0 on each router part of 3 different > networks? I very much doubt the above was quoted on the LARTC HOWTO. Please point us to where you saw this. It is completely wrong. First, 10.0.0.0/31 would be a network address. Second, a 31 bit subnet is meaningless. It only offers two addresses, the network address at 10.0.0.0 and the broadcast address at 10.0.0.1. That leaves no available addresses for host addresses. You probably mean /30 instead of /31. If you were using a /30, then you would run: ip addr add 10.0.0.1/30 dev eth1 ip addr add 10.0.0.5/30 dev eth2 ip addr add 10.0.0.9/30 dev teql0 The .1, .5, and .9 would be the first available addresses in their respective subnets. On router B, you would run: ip addr add 10.0.0.2/30 dev eth1 ip addr add 10.0.0.6/30 dev eth2 ip addr add 10.0.0.10/30 dev teql0 The .2, .6, and .10 addresses would be the second and final available host addresses on their respective subnets. And yes, each device sits on a different network when configured like this. The teql0 device simply lets you load balance across the two eth devices. > 2) What is the reason for doing the "/31" thing? CAn't we use network > addresses such as 192.168.0.0/24, 192.168.10.0/24 and so on for the > devices eth1, eth2 and teql0? You could use the 192.168.0.0/24 type addresses just as easily. The only difference is in how many addresses are available for hosts on the network block. By using a /30, you allow 2 host addresses and only 2 host addresses. Using the /24 network, you allow 254 host addresses. That seems rather wasteful when all you need is 2, doesn't it? Eliot Gable Certified Wireless Network Administrator (CWNA) Certified Wireless Security Professional (CWSP) Cisco Certified Network Associate (CCNA) CompTIA Security+ Certified CompTIA Network+ Certified Network and System Engineer Great Lakes Internet, Inc. 112 North Howard Croswell, MI 48422 (810) 679-3395 (877) 558-8324 Now offering Broadband Wireless Internet access in Croswell, Lexington, Brown City, Yale, Worth Township, and Sandusky. Call for details.http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc _______________________________________________ LARTC mailing list LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
