Page 2 of 2 FirstFirst 12
Results 11 to 17 of 17

Thread: Bridge with switch or gateway?

  1. #11
    psusi is offline Ubuntu addict and loving it
    Join Date
    Sep 2005
    Location
    Orlando, FL
    Beans
    3,980
    Distro
    Ubuntu Development Release

    Re: Bridge with switch or gateway?

    Quote Originally Posted by bab1 View Post
    Not so. See here. The effect may be the same in some cases but the devices are distinctly different.
    There isn't anything in that article that contradicts what I said, but since you take issue with it, let me clarify. A bridge forwards packets between network segments when they are addressed to a device on the other segment. A switch essentially treats every port as its own network segment and bridges between them. Bridging the two interfaces in Linux makes the computer behave just like a two port switch would, including the use of the 802.1D spanning tree protocol.

    Quote Originally Posted by bab1 View Post
    Why can't you have 2 routers in the chain. Each router is a hop.
    I said you can, but configuring the computer to be an IP masquerading router behind the IP masquerading wireless router is a bit overkill, and it sounded like the OP would rather have the computers be able to directly speak with the wireless router.

    Quote Originally Posted by bab1 View Post
    Huh???But it did not work. As Xyem said
    That does not mean it can't when configured correctly.

  2. #12
    Join Date
    May 2008
    Location
    SoCal
    Beans
    Hidden!
    Distro
    Ubuntu 14.04 Trusty Tahr

    Re: Bridge with switch or gateway?

    So you are saying that if 2 hosts with differing IP networks are connected to a switch they will communicate. Bridging is not built into switches as far as I know.
    -BAB1

  3. #13
    psusi is offline Ubuntu addict and loving it
    Join Date
    Sep 2005
    Location
    Orlando, FL
    Beans
    3,980
    Distro
    Ubuntu Development Release

    Re: Bridge with switch or gateway?

    Quote Originally Posted by bab1 View Post
    So you are saying that if 2 hosts with differing IP networks are connected to a switch they will communicate. Bridging is not built into switches as far as I know.
    No, I am not. Bridging takes place at the Ethernet layer, not the IP layer. Switches bridge every port to every other port, which is why any device can send Ethernet frames to any other device on the same network.

    It helps to think of the difference between a hub and a switch. A hub just forwards the electrical signals directly between all ports without any intelligence, creating a single network segment for all the connected hosts. A switch is smart enough to look at the destination mac address and only forward the packet to the correct port. That process is also known as bridging. It used to be that most people would use hubs to connect most of the computers on the network, then connect the two hubs to each other with a bridge, which was essentially just a 2 port switch.

  4. #14
    Join Date
    May 2008
    Location
    SoCal
    Beans
    Hidden!
    Distro
    Ubuntu 14.04 Trusty Tahr

    Re: Bridge with switch or gateway?

    Bridge devices are for bridging 2 differing IP networks via MAC tables. See the BSD man pages Yes I know the difference between layer 2 and Layer 3.

    That being said, your notion of not having to define routing at host A has led me to think of other solutions. How about no routing or bridging configuring. Place all the hosts on the same IP network (such as 192.168.1.0/24) and add a 2nd switch (a $10 4 port device) to connect both the original switched (hosts a,b,c,d) and the wlan0 interface to each other and the router. See my attached jpg
    Attached Images Attached Images
    -BAB1

  5. #15
    psusi is offline Ubuntu addict and loving it
    Join Date
    Sep 2005
    Location
    Orlando, FL
    Beans
    3,980
    Distro
    Ubuntu Development Release

    Re: Bridge with switch or gateway?

    Quote Originally Posted by bab1 View Post
    Bridge devices are for bridging 2 differing IP networks via MAC tables. See the BSD man pages Yes I know the difference between layer 2 and Layer 3.
    No, bridges connect two networks at layer 2. A ROUTER forwards IP packets between two IP networks.

    Quote Originally Posted by bab1 View Post
    That being said, your notion of not having to define routing at host A has led me to think of other solutions. How about no routing or bridging configuring. Place all the hosts on the same IP network (such as 192.168.1.0/24) and add a 2nd switch (a $10 4 port device) to connect both the original switched (hosts a,b,c,d) and the wlan0 interface to each other and the router. See my attached jpg
    The problem the OP has is that he does not HAVE a wire to the router ( switch A in your diagram ), so he wants to bridge his switch to the one with the router via the wireless.

  6. #16
    Join Date
    Jul 2008
    Location
    $HOME
    Beans
    177
    Distro
    Ubuntu 8.04 Hardy Heron

    Re: Bridge with switch or gateway?

    Dont worry about your switch dropping the packets, the switch will know where to send the packets (think of a cheap wireless router, essentially a switch with a WLAN card built-in and they're bridged . See my point. It will work.
    Ubuntu 8.04/Dell Inspiron 700m Intel Celeron D 1.67Ghz 756MB G.Skill/60GB HDD
    Ubuntu 8.10 Intrepid AMD64bit SE/Custom XFX mobo/AMD Phenom X3 2.1Ghz/4GB G.Skill DDR2 800Mhz/1840GB HDD(4)

  7. #17
    Join Date
    Dec 2006
    Beans
    178
    Distro
    Ubuntu 8.10 Intrepid Ibex

    Re: Bridge with switch or gateway?

    My apologies to everyone who has contributed their knowledge, the forum wasn't e-mailing me and it wasn't showing up in my subscribed threads with unread messages.

    I think that the physical set-up ( at least, my description of it ) is causing confusion. Would it be easier if I doodled a diagram ( or used Dia ) of it?

    I'll try again to describe it in words.

    In my room I have 4 computers ( A, B, C, D ) connected together with this wired switch using their eth0 interfaces. Computer A also has a wlan0 interface.
    Elsewhere in the house, there are several laptops and a computer ( E ) which connect to the router ( Linksys WRT54G ) using wireless and wired connections. Computer A also connects to the router through wlan0.

    What I would like to do is get computer A to bridge the network attached to its eth0 and the one on its wlan0 so that computer B could "talk" to computer E through its eth0/only interface:
    Computer B -> ( Wired ) -> Computer A -> ( Wireless ) -> Router -> ( Wired ) -> Computer E
    Also, this would mean computer B could get its IP through DHCP:
    Router -> ( Wireless ) -> Computer A -> ( Wired ) -> Computer B

    So far, when I bridge eth0 and wlan0 on computer A I witness the following:
    Pinging computer A from computer B with a large packet size shows ( in bwn-ng ) activity on eth0 and br0 ( this is how I expect it would behave ) on computer A.
    Pinging computer E from computer B in the same way results in no activity at all ( and ping shows errors ). Pinging E and B from A is fine.

    From this, I concluded ( with my limited network knowledge ) that the switch between computer A and B is dropping the packets because computer E is not attached to it, instead of sending them to computer A to be "relayed" over the wireless.

    Thanks for your patience and sharing your knowledge, it's very appreciated, enlightening and will be put to good use.

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •