MAC addresses are mapped to outgoing ports in the Forwarding Table If an

Mac addresses are mapped to outgoing ports in the

This preview shows page 98 - 104 out of 139 pages.

MAC addresses are mapped to outgoing ports in the Forwarding Table If an address is not found in the Forwarding Table, then the frame is broadcast out all ports (that is, switch reverts to acting like a hub). If frames are received on more than 1 port at the same time, this is no problem. Each is buffered and forwarded individually. Devices connected to a switch are in different collision domains Each switch port defines a separate collision domain Devices connected to a switch are in the same broadcast domain Switch will forward a layer 2 broadcast frame out every port except the one it came in on. Rami Ghannam, DePaul University 98 TDC 413
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Switched Ethernet Data delivery via intelligent switch Ethernet Switch Twisted Pair #4 #3 #2 #1 Example: PC #1 puts MAC address “#2” into Destination Address field of Ethernet header and transmits data frame to Switch Switch checks its MAC Forwarding Table and ONLY transmits data frame to #2. TDC 413 Rami Ghannam, DePaul University 99
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IP Router Operates at Layers 1, 2 and 3 IP packets received on any port are stored temporarily in a memory buffer and sent out an interface determined by the destination IP address in the IP header. IP subnets are mapped to outgoing interfaces in the Routing Table If an address is not found in the Routing Table, then If there is a default route , then the packet is forwarded based on this route. If no default route, the packet is dropped and an ICMP error message sent back to the sender. If frames are received on more than 1 port at the same time, this is no problem. Each is buffered and forwarded individually. Devices connected out different router ports are in different collision domains and different broadcast domains Routers do not forward layer 2 broadcast frames Rami Ghannam, DePaul University 100 TDC 413
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Forwarding Example: Client #1 sends to Web Server Rami Ghannam, DePaul University 101 IP Router Web Server IP 160.16.64.12 MAC 00:01:02:03:04:22 Interface Fa0/0 IP 160.16.0.1 MAC 00:01:02:03:04:02 Interface Fa0/1 IP 160.16.64.1 MAC 00:01:02:03:04:11 Client #1 IP 160.16.0.5 MAC 00:01:02:03:04:09 Client #3 IP 160.16.0.10 MAC 00:01:02:03:04:07 Ethernet Hub Ethernet Hub Client #2 IP 160.16.0.11 MAC 00:01:02:03:04:06 Ethernet Switch Fa0/0 Fa0/1 Fa0/2 TDC 413
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Decision Factors in Physical Plant 102 Network topology Cost per location Distance Limitations Other Limitations (interference) Bandwidth (data flows, type) TDC 413 Rami Ghannam, DePaul University
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Ethernet Physical Standards Ethernet can run over several different types of physical cables (copper wire, coaxial cable, optical fiber) at several different transmission rates (10 Mbps, 100 Mbps, 1 Gbps, 10 Gbps) For each (cable type, data rate) pair, there is a unique layer 1 (physical) Ethernet standard defined by the IEEE 802.3 committee There is only one layer 2 Ethernet standard , specifying packet header format, access methods, switch operations, that works over any of these different physical networks.
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