On Mon, Jun 21, 2010 at 9:52 AM, eckinator <eckina...@gmail.com> wrote: > 2010/6/21 Adam Maas <a...@mawz.ca>: >>>> >>>> [...] Since current WiFi tech is based off of Ethernet, your >>>> wireless adapter will have a MAC address (which may be >>>> shared with the ethernet port or unique to the wifi controller). >>> >>> The latter would be el cheapo in the worst way as you wouldn't be able >>> to have connections open on wired and wireless LAN at the same time. I >>> doubt that even exists to be honest. >> >> Actually it's not terribly cheap and doesn't prevent you having wired >> and wireless connections unless your WAP is very cheap and functions >> as a bridge rather than a proper access point (with a separate >> wireless segment). MAC addresses need to be unique on the network >> segment, not globally (they are assigned as globally unique to ensure >> this, but don't actually have to be). Most hardware has at least >> limited MAC reassignment capabilities these days and it's a waste of >> MAC address space to assign two MAC addresses to the same piece of >> silicon so it sometimes doesn't happen. > > bear with me if i am getting something wrong but if two physical > interfaces using the same MAC are both connected how will the IP stack > know what to route where? is this done simply by eth0 thru x mappings > or what am i missing out on? and can you name an example of such > hardware, please? and why would anyone risk their product running into > the unique per segment restriction? i know enough people who have > their laptops docked to their work LAN and the wireless on that the > same time into their work LAN without routed/separated segments - IRL > and in small firms this does happen more often than not > cheers > ecke >
The IP stack routes based on IP not hardware addressing, it's running at layer 3 and never sees the MAC address. Layer 1 & 2 are handles by the hardware and the drivers respectively. Typically routing implementations are by IP and associated network interface (eth0 et al). The drivers and hardware get the traffic from the stack in separate buffers based on physical interface, MAC addresses really only have a function when the hardware/driver is listening to incoming traffic on the interface. Most Wifi setups are segmented from the wired LAN from the WAP, which is usually the router for both the Wifi and Wired so it while it looks like a bridged connection, it's actually two separate segments. It's rare to have a WAP running in bridged mode since the WAP then has to rebroadcast all the traffic on the wired segment which leads to additional congestion. Generally you have the Wifi on the same subnet but a different segment in smaller organizations and a completely different subnet and routed segment for larger implementations. -Adam -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
