802.1 vLAN meeting, 3/12/96, 10:20pm, LaJolla, Ca. MEDIA OR NETWORK BASED vLANs ? (document # 96/020) presentation, John Bartlett - Agile Networks - - - - - - Canonical System Media Based vLAN Logical View Consequences of Media based vLANs Network based vLAN logical View Consequences of Network based vLANs - - - - - - vLAN definition - A vLAN is an administratively defined logical grouping of LAN stations independent of their physical location within a Bridged LAN infrastructure - A vLAN is a definition of the segments included in a broadcast domain - A vLAN is a community of interest, defined by some common application, to which we sould like to limit the distribution of information, to enhance network performance, scaleability and security. - Key question for this presentation: -Is a vLAN limited to a particulat media type (802.3 or 802.5), or can it span them? -OR, is translation always done when changing media types? - - - - - - Canonical System -picture (left to right...) Station A on Ethernet going to a bridge/switch going to FDDI. FDDI going to bridge/switch to Token Ring Token Ring to another bridge/switch to an Ethernet segment and Station B For Traffic flowing from Station A to Station B: -Should frames be translated each time they cross from one media type to another? (Media based vLAN) -Or should frames be encapsulated and distributed throughout the network to points where they are needed? (Network based vLAN) - - - - - - MEDIA BASED vLAN logical view picture... various vLANs ... classified with types... .. only same type on the same type media... (traffic on FDDI is classified as vLAN and type...) -All traffic changing media types is translated -vLANs are limited to a media type - - - - - - Consequences of Media based vLANs -Translation may be done from type A to type B and then back to type A -Network wide view of a common vLAN requires incorporating sub-vLANs into a common network vLAN -Frames cross each link at most one time - - - - - - Network based vLAN Logical View -(picture) picture... various vLANs ... classified with types... .. *different* types of vLANs on the same media..., (required denotation...) --nested vlans, with denotations of vLAN ID and vLAN type - Traffic is sent into the network in as many forms as necesary to suppport the network's current requirements - Translation does not occur if final media type is the same as initial media type - Now possible to have translation bridges as a network resource. - - - - - - Network based vLAN logical View (same picture as previous slide...) on edges... xlation bridge - Translation bridge as network resource - - - - - - Consequences of Network based vLANs - Translation is simplified, data is only translated when the end stations are on different media - Possible to have a simgle translation bridge resource in the network (one-arm translator) - Consistent with a ATM LANE model - More that one copy of a frmae may cross any given link (multicast / unknown case only) - MTU size problem (TR-Ethernet-TR) - vLANs still have to be defined as being bound to a media type