Bridging in Networking

Bridging in Networking

• 1.
  BRIDGING
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  WHAT IS BRIDGING??? Bridge is used to connect two or more different LAN networks.  It is a device used to connect LAN cable segment together.  Bridge operates at Data-Link Layer.  It can connect on different architecture like Ethernet and Token-ring.
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  WHY DO WEUSE BRIDGING???  It provide Packet Filtering, meaning it only passes the packet that are allow on destination Network
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  HOW IT WORKS??? Bridge examine each packet as it enters through one of the port, it first check MAC address of the sender and create a mapping between the port and the sender MAC address. Then it looks the MAC address of Destination and compare the list of all learned MAC addresses. If the address is in the list then bridge look up the port number and forward the packet to the port where the destination is connected. If the destination’s MAC address is not in the list, the bridge blocks the data from passing.
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  CHARACTERISTICS OF BRIDGES RoutingTables  It contain one entry per station of network to which bridge is connected.  It is used to determine the network of destination station of a received packet. Filtering  It is used by bridge to allow only those packet destined to the remote network.  Packets are filtered with respect to their destination and multicast addresses. Forwarding The process of passing the Ticket from one network to another. Learning Algorithm The process by which the bridge learns how to reach stations on the internetwork.
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  TYPES OF BRIDGING Transparent Bridging  Translational Bridging  Source-route Bridging  Local Bridging  Remote Bridging
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  TRANSPARENT BRIDGING  Alsocalled learning bridges.  Build a table of MAC addresses as frames arrive.  Ethernet networks use transparent bridge. Duties of transparent bridge  Filtering Frames  Forwarding  Blocking
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  TRANSLATIONAL BRIDGING  Usefulto connect segments running at different speeds or using different protocols such as token Ring and Ethernet networks.  Translational Bridge can add or remove information and fields from frame as needed.
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  SOURCE-ROUTE BRIDGING  Usedin Token Ring networks.  Each station should determine the route to the destination when it wants to send a frame and therefore include the route information in the header of frame.  Addresses of these bridges are included in the frame.  Frame contains not only the source and destination address but also the bridge addresses.
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  LOCAL BRIDGING  MAC-layerBridge  Provides packet filtering and repeating services for the network segments of the same type.  Simplest type of Bridge because it has no need for packet filtering or buffering.  This Bridge simply propagates the incoming packets to the appropriate ports or discard them.
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  REMOTE BRIDGING  Connectsnetwork segments at different locations, using WAN link such as MODEM or Leased line. The difference in speed between Local and wide area links.  Remote Bridge uses internal buffer to store the data received from LAN while it is waiting for transmission to the remote site.
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  ADVANTAGES OF BRIDGING It is simple and significant.  It prevents unnecessary traffic from crossing onto network.  It helps to isolate the busy network to not-so-busy network.
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  DISADVANTAGES OF BRIDGING It is slower than HUB & repeater because they examine each frame’s source and destination addresses.  Bridge provide no protection against Broadcasting.  Bridge cant make decision about routes through the Network.  Expensive
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  WIRELESS AND WIREDBRIDGING Wired Bridging  Work on Layer 2 in OSI Model  Only know about MAC Address Wireless Bridging (Wireless Access Point)  Work on Layer 3 in OSI Model  Know about IP address, Subnet Mask, Routing etc.
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  THANK YOU…