2002 - cesnet

SLU Karviná59 639 8xxxTU Ostrava59 699 xxxx59 732 xxx0, 785SLU Opava55 368 4xxx9*0Univ. of PardubiceČ. Třebová465 533 006465 534 00883Pardubice46 603 6xxx46 603 7xxx46 603 8xxx22CU FPh Hradec Králové49 506 7xxx5566Univ. of Hradec Králové49 506 1xxxPublic networkTU Liberec48 535 xxxx40/47CESNET2NIX.CZInternet858SBU Č. Budějovice38 777 xxxx38 903 xxxx7MU Brno5 4151 2xxx0*89894#0Cern70841Geneva, CERN00 412 276 xxxxxBrno UT5 4114 xxxxCU Praha CTU Praha2 2449 1xxx 2 2435 xxxxCAS IPh Praha2 6605 9999UE Praha2 24095 xxxFigure 8.3: Scheme of IP telephony network8.3 IP Phones SupportDuring 2002, we further concentrated on the issues of IP phones, based onH.323. For internal needs, we reserved 76xxxxxxxx numbers in the numberingplan of the IP telephony network. In order to increase the availability andsecurity of the service, it is necessary to make use of a distributed architectureof interconnected GKs, forming zones that will refer to redundant central GKs.In case of a failure in the connection at the central GK, calls can only be madewithin the local zone.We focused on the testing of convenient GKs, in close collaboration with Kerio,which has been developed the GK application. Kerio provided the GK for use inCESNET’s network free of charge. In the laboratories of TU in Ostrava, we testedcalls from IP phones among zones formed by four GKs, linked to the central GKat gk.ext.cesnet.cz, located at CTU Prague.We deployed the Kerio VoGW voice gateway for Linux, with a passive ISDN/BRIcard connected to the central exchange. Our aim was to find a less expensive112 High-speed National Research Network and its New Applications 2002