Does anyone have an IP that involves a load balancing router to test with?
On Mon, Oct 31, 2016 at 5:54 PM, Bryan Holloway <br...@shout.net> wrote: > On 10/31/16 4:20 PM, Olivier Benghozi wrote: > >> Hi Randy, >> >> >> ECMP loadbalancing is most frequently done on layer3+layer4 headers, and >> unixlike traceroute use UDP with increasing destination port number for >> each packet (usually starting at 33434), which allows to see the different >> available paths, as wrote William. >> >> Would you want/need to stick to only one traceroute path, you may use >> ICMP traceroute instead of UDP traceroute (no port in ICMP, so only layer 3 >> available to loadbalance, so all packets will go through the same >> interface). >> >> Usually it is achieved by using traceroute -I yourdest >> Windows tracert is ICMP only traceroute by the way. MTR tool is also ICMP >> based by default. >> >> Keep in mind that it looses some useful information, though (since you >> see only one path and don't decide which). >> So, you can also use UDP traceroute with fixed port (by example 33434 >> with no port increase), and try again the same traceroute with another >> destport (with fixed port too, by example 33435), which would display two >> different paths in a more readable way. RTFM is required since the options >> depend on your traceroute particular specie :) >> >> >> Olivier >> >> On 31 oct. 2016 à 20:42, William Herrin <b...@herrin.us> wrote : >>> >>> On Mon, Oct 31, 2016 at 3:33 PM, Randy <a...@djlab.com> wrote: >>> >>>> Any idea how a traceroute (into my network) could end up this fubar'd? >>>> Discovered this wierd routing while investigating horrendously slow >>>> speeds >>>> (albeit no packet loss) to a particular ISP abroad. >>>> >>> >>> Hi Randy, >>> >>> This is per-packet load balancing. In the forward path the alternates >>> are different lengths but the traceroute stops as soon as at least one >>> of the paths reaches the destination. >>> >>> The return path is also engaged in per-packet load balancing but the >>> paths are all the same length. >>> >> >> > This is also a handy tool that addresses the same issues: > > https://paris-traceroute.net/ > >
