The Illustrated Network- P63 potx

... the messages (the more text avail- able, the better) or by simply fi nding out the “secret” key (the basis of many old spy movies). The key is the weakest point of the system: You can’t use the ... is the point. The page and lock are shown in Figure 23.5. IE7 moves the lock to the top of the page, but it’s the same lock. We can always view the certifi cate again...

Ngày tải lên: 04/07/2014, 08:20

... of, the physical address used by the frames that carry the packets between adjacent systems. Why should the systems need two addresses for the two layers? Why can’t they just both use either the ... 3, which forwards the data, is the destination reachable.) These forwarding decisions are made at the TCP/IP network layer. The Network Layer The network layer delivers dat...

Ngày tải lên: 04/07/2014, 07:20

... point-to-point links), they came up with the term “datagram.” The IP layer of the whole TCP/IP protocol stack is the very heart of TCP/IP. The frames that are sent and delivered across the network from ... learn about the IP layer. We’ll start with the fi elds in the IPv4 and IPv6 packet headers. We’ll discuss most of the fi elds in detail and show how many of them relat...

Ngày tải lên: 04/07/2014, 07:20

... numbers every time they are run. The server has no trouble replying to the proper client because the server can just reverse the source and destination port numbers to send a reply to the correct ... don’t want to add these to the application? Files cannot use quick request–response messages to transfer themselves over a network. That’s the job of TCP, which is the topic of...

Ngày tải lên: 04/07/2014, 07:20

... rules ϭ Gig Ethernet Note: All links use 10.0.x.y addressing only the last two octets are shown. FIGURE 13.1 The hosts on the LANs have routing tables as well as the routers. The ISPs on the Illustrated ... on the hosts on the LANs, as shown in Figure 13.1. But we’ll also discuss, for the fi rst time, how the two ISPs on the network (called Ace ISP and Best ISP) relat...

Ngày tải lên: 04/07/2014, 07:20

... such as the IXPs. This is one reason that Ace ISP and Best ISP in Figure 13.1 at the beginning of the chapter maintain multiple links between the four routers in the “quad” between their border ... collection of other ISPs just like Ace and Best. Can LAN1 reach LAN2 through the Internet”? Maybe. It all depends on the arrange- ments between our two ISPs and the ISPs at the...

Ngày tải lên: 04/07/2014, 07:20

... fxp0.0 disable; The local keyword means that the local router is the RP. The address is the RP address that will be used in PIM messages between the routers. The confi guration on the non-RP router, ... So, the source’s router (actually, the DR) encapsulates the multicast packets inside a unicast packet sent to the RP and tunnels the packet to the RP in this form...

Ngày tải lên: 04/07/2014, 08:20

... into one stream and carrying them all over the total bandwidth on the same “unchannelized” fi ber optic link. If there are voice, video, and data channels on the link, these are now virtual channels ... and terminate in the same equipment—not only at the physical layer, but at some layer above the lowest. On modern Metro Ethernet links, the convergence is done by combining th...

Ngày tải lên: 04/07/2014, 08:20

... is one of the most secure fi rewall types that can be deployed. The proxy sits between the protected network and the rest of the world. Every packet sent outbound is intercepted by the proxy, ... other fi rewall fi lters, are also applied to an interface in the outbound or inbound direction (or both). However, the traffi c on the interface must be sent to the AS PIC in ord...

Ngày tải lên: 04/07/2014, 08:20

... and Interfaces 27 Encapsulation 28 The Layers of TCP/IP 30 The Physical Layer 30 The Data Link Layer 32 The Network Layer 35 The Transport Layer 38 The Application Layer 41 Session Support ... xxiii About the Author xxx PART I Networking Basics CHAPTER 1 Protocols and Layers 3 The Illustrated Network 7 Remote Access to Network Devices 8 File Transfer to a Router 1...

Ngày tải lên: 04/07/2014, 07:20