XenProject.org user apit submits the following: --- I am running Xen 4.1.5 on Linux Ubuntu 12.04 LTS and ping on guest sometimes is extremely high (see in attachment). When I was using Xen 4.1.2 ping was high on both - host and guest. xm info host : server release : 3.5.0-44-generic version : #67~precise1-Ubuntu SMP Wed Nov 13 16:16:57 UTC 2013 machine : x86_64 nr_cpus : 8 nr_nodes : 1 cores_per_socket : 4 threads_per_core : 1 cpu_mhz : 2992 hw_caps : bfebfbff:20100800:00000000:00000940:000ce3bd:00000000:00000001:00000000 virt_caps : total_memory : 32761 free_memory : 406 free_cpus : 0 xen_major : 4 xen_minor : 1 xen_extra : .5 xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p xen_scheduler : credit xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : unavailable xen_commandline : placeholder dom0_mem=1024M cc_compiler : gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) cc_compile_by : stefan.bader cc_compile_domain : canonical.com cc_compile_date : Tue Dec 17 16:35:34 UTC 2013 xend_config_format : 4 --- The original post and the attachment apit submitted can be found here: http://xenproject.org/questions-and-answers/high-ping-latency-on-guest.html The attachment shows a ping output which averages about 49 ms but shows a blip of 321 ms before returning to 49 ms. Any insights? Please respond to me (so I can crosspost) or visit the website directly. Thanks, Russ