tailieunhanh - The Illustrated Network- P28

The Illustrated Network- P28:In this chapter, you will learn about the protocol stack used on the global public Internet and how these protocols have been evolving in today’s world. We’ll review some key basic defi nitions and see the network used to illustrate all of the examples in this book, as well as the packet content, the role that hosts and routers play on the network, and how graphic user and command line interfaces (GUI and CLI, respectively) both are used to interact with devices. | CHAPTER 9 Forwarding IP Packets 239 bsdserver Inxclient winsvr2 wincli2 eth0 MAC 00 0e 0C 3b 87 32 Intel_3b 87 32 IPv6 fe80 20e cff fe3b 8732 eth0 MAC 00 b0 d0 45 34 64 Dell_45 34 64 IPv6 fe80 2b0 d0ff fe45 3464 LAN2 MAC 00 0e 0c 3b 88 56 Intel_3b 88 56 IPv6 fe80 20e cff fe3b 8856 LAN2 MAC 00 02 b3 27 fa 8c IPv6 fe80 202 b3ff fe27 fa8c Ethernet LAN Switch with Twisted-Pair Wiring 240 PART II Core Protocols the entry has a preference of 10 which makes it more costly to use than direct local interface routes 0 or static routes 5 . Traffic to destinations on LAN1 is sent to PE1 over the ge-0 0 3 interface. A preference is distinct from the metric or cost of a route itself preference applies to routes learned in different ways. We can make the routing table display more Cisco-like by using the terse option admin@CE6 show route 16 terse 34 destinations 35 routes 34 active 0 holddown 0 hidden Active Route - Last Active Both A Destination P Prf Metric 1 Metric 2 Next hop AS path 24 O 10 6 ge-0 0 24 D 0 fe-1 3 32 L 0 Local The asterisk means the route is active used for forwarding and the P field is for protocol. One metric is used two are allowed the next-hops are the same thankfully and we ll talk about what an AS path is in the chapter on the BGP routing protocol. Let s use traceroute to see which routers CE6 uses to reach LAN1 attached to router CEO at interface . admin@CE6 traceroute traceroute to 30 hops max 40 byte packets 1 ms ms ms 2 ms ms ms 3 ms ms ms 4 ms ms ms 5 . 1 ms ms ms Each router handles the three-packet set generated by the source CE6 in one of three ways 1. If the packet is not for this router the device does not have .