While I might be offering a very simple view, and forgive me if I am, but I have a question.
If you disconnect the two connections, and run with a single connection only, do you receive better ping times individually? For example, if eth0 = wired and eth1 = wireless, if you leave eth0 down and ping using eth1 do you get varying latencies? And do you get equivalent results (no equal latencies) for doing the same test with eth0? Assuming that you can mathematically determine which link is getting the better latency, would not a script that checks the efficiency say every 10/15 seconds be worthwhile to look into. For example : eth0,eth1,eth2 are all up, eth0 = wired ; eth1=wireless ; eth2 = lan. calculate ping times for the same point (needs to be same at all times) from eth0 and eth1, based on results, change the default gw and routes. consistentaly check this every 1 minute or so. I'm sure I'm over simplifying what it is you are doing, but I am curious as to you results. Regards, Joey ----- Original Message ----- From: "S Mohan" <[EMAIL PROTECTED]> To: "'[EMAIL PROTECTED] Sourceforge. Net'" <[EMAIL PROTECTED]> Sent: Friday, August 15, 2003 9:12 PM Subject: [leaf-user] Redundacy and multipath routing. > I use LEAF Bering 1.2. I wanted to experiment using it for link load > balancing and redundancy and ran up some hitches. Pointers would be welcome > and helpful. > > I set up a single machine with 2 ethernet interfaces as per the network > schematic below. > > > +----------+ A.B.64.175/26 > | |-------- eth0--------------- gw A.B.64.134 > | LEAF Box | > | |-------- eth1--------------- gw A.B.65.129 > +----------+ A.B.65.131/29 > > I have a third ethernet port that I can configure as 192.168.1.1 local LAN > interface.A.B.64.134 is a land link (approx 400ms latency) while A.B.65.129 > is a satellite link (approx 750ms latency). The latency was found by > changing default route and pinging the same target IP. > > [Case 1] > I first wanted to check if fail over from one interface to another works > using the metrics declarative in the routes for priority of routes. > > The commands I gave and the outputs are as under: > > # ip ad flush dev eth0 > # ip ad flush dev eth1 > # ip ad flush dev eth2 > # ip ad add dev eth0 A.B.64.175/26 > # ip ad add dev eth1 A.B.65.131/29 > # ip add ro default via A.B.64.134 metric 1 > # ip add ro default via A.B.65.129 metric 2 > # ping W.X.Y.Z > > [Result 1] > Pings responds with packet replies if both are connected. If I disconnect > the ethernet cable from eth0, the ping was still going thro'. If I connect > the cable on eth0 and disconnect eth1, ping stops. If I connect back eth1, > ping resumes with the icmp packet count at a much larger number than when it > stopped with the difference in packets shown as lost. > > I thought by looking at ping latency, I could make out which link is being > used. Latency was always 750ms. > > My surmise: > The originating IP for the ping is taken as A.B.65.131. Thus replies do not > land up if eth1 is not connected even though packets go out of eth0. If eth1 > was connected, it was used as a preferred route as originating IP was from > this subnet. > > [Question 1] > Am I wrong? Is my interpretation of metrics wrong? > > [Case 2] > I removed the default route and added a multipath route using commands as > under: > > # ip ro del default > # ip ro del default > # ip ro add default nexthop via A.B.64.134 dev eth0 weight 1 \ > nexthop via A.B.65.129 dev eth1 weight 1 > > [Result 2] > Giving a ping here had the same results as in [Result 1]. I expected each > ping packet to have different latency switching between 450 and 750ms. Did > not happen. Latency was 750ms consistently. > > [Case 3] > The above weight go by flows and not packets. Maybe a single single ping is > treated as one flow. I changed the multipath to include equalize using > commands as under: > > # ip ro del default > # ip ro add default equalize nexthop via A.B.64.134 dev eth0 weight 1 \ > nexthop via A.B.65.129 dev eth1 weight 1 > > [Result 3] > Same as [Result 1] and [Result 2]. Atleast here I should have got latencies > switching between 450 and 750ms for alternating ICMP requests. > > [Questions] > 1. Is this method of testing correct? > 2. Are there any other utilities/ methodologies that I can use to test this > better? > 3. Is expecting load balancing/ redundancy to happen for a single flow > wrong? > > TIA > Mohan > > > > ------------------------------------------------------- > This SF.Net email sponsored by: Free pre-built ASP.NET sites including > Data Reports, E-commerce, Portals, and Forums are available now. > Download today and enter to win an XBOX or Visual Studio .NET. > http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01 > ------------------------------------------------------------------------ > leaf-user mailing list: [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/leaf-user > SR FAQ: http://leaf-project.org/pub/doc/docmanager/docid_1891.html ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. Download today and enter to win an XBOX or Visual Studio .NET. http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01 ------------------------------------------------------------------------ leaf-user mailing list: [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/leaf-user SR FAQ: http://leaf-project.org/pub/doc/docmanager/docid_1891.html
