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Because the hub is effectively the backbone, there is no backbone cabling specification. Instead, hubs can be linked together using a special crossover cable. The pinout is illustrated in Figure 4.13. NOTE Figure 4.13. Ethernet 10Base-T station-to-hub interconnect and hub-to-hub crossover cable. As an alternative to using a crossover cable, certain hub manufactures provide an MDI/MDI-X port. This port is wired with a switch that can change the pin signals so the port can behave as a crossover or straight-through port. This is a nice feature as it eliminates the need for the crossover cable. It is not available on multiport bridges (or switches), however, which follow the same device interconnection scheme. A 10Base-T hub-to-hub crossover link has the same maximum distance (100m) as a station-to-hub interconnection. In addition to the maximum distance between hubs, no end-station can be separated by more than four hubs connected tougher by five 10Base-T cable segments for a total cable distance of 500m. It is possible to have more than one hub connected to an end-station (see Figure 4.14).
Figure 4.14. 10Base-T hub-to-hub interconnection using 10Base-T cabling. To provide for greater network distance, it is common to use a 10Base-5 for backbone cabling. This allows for longer distances between hubs and eliminates the hub cascading limitation by forcing the 10Base-5 backbone to provide the interconnection link between 10Base-T hubs. Most manufacturers provide an AUI or BNC interface on 10Base-T hubs just for this purpose. For longer distances beyond 500M, 10Base-FL (which can support link distances up to 2,000m) can be used. Figure 4.15 illustrates a 10Base-5 backbone with 10Base-T hubs.
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Understanding the Network A Practic
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IOS Authentication and Accounting S
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About the Reviewers These reviewers
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Tell Us What You Think As the reade
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mostly dealt with interconnecting m
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• A short introduction to SNMP Ap
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In theory, a computer network can o
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Coaxial cable has a single solid co
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• Radio transmission—It is achi
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• Baseband transmission applies t
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Ring Topology Figure 1.3. The bus t
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Packets and frames are often used a
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Asynchronous transmission involves
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Figure 1.6. Collision handling unde
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In a ring topology, a token is pass
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Repeaters The repeater was introduc
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the network. If your 50-node networ
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Figure 1.12. A collection of nodes
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their destination, type, and conten
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shop, you are using Novell's Direct
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Figure 1.14. The OSI and Internet r
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Layer 7: Application This layer pro
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end-to-end, sequenced data delivery
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outer, the delivery path might be d
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and network transport is a very imp
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Figure 1.16. The "bottom up" commun
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Chapter 2. The Networker's Guide to
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Internet Society, a nonprofit organ
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• First, it performs translations
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Figure 2.2. The IP header. • Vers
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To assist in the reassembly process
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Figure 2.3. IP address classes comp
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taking the natural mask of the addr
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Classful Subnetting Examples The im
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21 2,000 8,000 255.255.248.0 22 1,0
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classful-based address space model.
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Table 2.6. Classless Network Addres
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NOTE Because CIDR is used for addre
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will connect in the future, it is b
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Routers are also called intermediat
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IP datagrams for which the local ho
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1. The Layer 3 to Layer 2 address m
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3. Router B—Router B receives the
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connected networks. Figure 2.11 ill
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Figure 2.12. A simple regional (ISP
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gw1, gw2, gw4 3 gw1, gw3, gw4 3 gw1
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Dynamic routing might not be requir
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The transport layer as a whole repr
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window to reflect changes in the pa
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The TCP Header The TCP header provi
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53 DNS (Domain Name Service) 67 BOO
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SNMP Simple Network Management Prot
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uses both TCP and UDP for service d
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RFC 974 Mail routing and the domain
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Figure 3.1. Physical versus logical
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Figure 3.2. The AppleTalk protocol
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AppleTalk Address Resolution Protoc
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of 400 microseconds, in addition to
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Along with the SAP, there is a 5-by
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delivery is a best-effort delivery
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• DDP checksum (long header only)
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eachable within the internetwork. T
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information from the router's other
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AppleTalk Update Based Routing Prot
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• type is the service classificat
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application layers. AppleTalk has n
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Figure 3.10. ZIP message formats. E
Page 137 and 138: Printer Access Protocol Printer Acc
Page 139 and 140: Figure 3.11. Novell (IPX) protocol
Page 141 and 142: The other nodes on the network that
Page 143 and 144: Figure 3.13. IPX datagram format.
Page 145 and 146: the cumulative information gleaned
Page 147 and 148: • Hop Count is the number of rout
Page 149 and 150: Upper Layer Protocols IPX is used t
Page 151 and 152: Msg.Add.Name Adds a unique name to
Page 153 and 154: Related RFCs RFC 1001 RFC 1002 RFC
Page 155 and 156: service enhancement or replacement
Page 157 and 158: Figure 4.1. The LLC interfaces in r
Page 159 and 160: it does not provide for error recov
Page 161 and 162: and smooth pattern flow enables MTL
Page 163 and 164: cabling, backbone length 800m Categ
Page 165 and 166: combination of light refraction and
Page 167 and 168: NOTE Cladding is the glass "shell"
Page 169 and 170: Ethernet The original Ethernet prot
Page 171 and 172: UTP telephone cabling infrastructur
Page 173 and 174: Since the introduction of the IEEE
Page 175 and 176: In the event that two Ethernet end-
Page 177 and 178: The 802.3 frame type used in Figure
Page 179 and 180: • Frame check sequence (4 bytes)
Page 181 and 182: • Physical layer signaling (PLS)
Page 183 and 184: cable segment length (for coaxial s
Page 185 and 186: transmission medium using BNC (Brit
Page 187: Figure 4.12. A basic 3-cable 10Base
Page 191 and 192: Figure 4.16. 10Base-T in a consulta
Page 193 and 194: • Support for full-duplex operati
Page 195 and 196: mechanisms, in terms of encoding an
Page 197 and 198: etween different PHY encoding imple
Page 199 and 200: 100Base Ethernet) is based on the p
Page 201 and 202: The Gigabit PHY The Gigabit PHY con
Page 203 and 204: CSMA/CD is sensitive to operating r
Page 205 and 206: The main advantage of using FDR ove
Page 207 and 208: have to transmit against the priori
Page 209 and 210: • Ring timing maintenance—The A
Page 211 and 212: check the lobe cable. If the lobe t
Page 213 and 214: Token Ring addresses are expressed
Page 215 and 216: • Report Active Monitor Error (RA
Page 217 and 218: they first join the ring or in the
Page 219 and 220: Figure 4.22. The IBM type 1 MIC con
Page 221 and 222: FDDI Work on the Fiber Distributed
Page 223 and 224: However, all this comes at a cost,
Page 225 and 226: Figure 4.25. FDDI MAC data frame an
Page 227 and 228: topologies needed for the transmiss
Page 229 and 230: Chapter 5. WAN Internetworking Tech
Page 231 and 232: Placing a Call The functional model
Page 233 and 234: LATAs to provide local exchange ser
Page 235 and 236: The PSTN was originally designed fo
Page 237 and 238: sampling rate is 8,000 times per se
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Figure 5.1. A multiplexer from a lo
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Table 5.1. The American (DS) and In
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The M24/D4 frame standard is the ba
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contains consecutive ones and zeros
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• Line loopback/line build-out (L
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process. The T3 multiplexer adds st
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committee. The committee provided t
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The photonic layer defines the elec
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such as T1/E1, FDDI, and others. Th
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SS7 signaling components are connec
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SCCP operates as an OSI-RM Layer 3.
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WAN point-to-point links. It can be
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Figure 5.11. The ISDN protocol refe
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• The R interface acts as a point
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• Flag—This is an 8-bit (011111
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terminals attached to the ISDN swit
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X.25 networks are comprised of four
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Frame Relay, like the ISDN effort i
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• Flag—This functions as a fram
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Figure 5.17. the B-ISDN reference m
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environments is implemented using A
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endpoints. A Virtual Path Link (VPL
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ATM endpoints. The user adaptation
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1. The ATM end-device issues a setu
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Data-Link Framing Point-to-point de
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PPP PPP can provide multiprotocol d
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PPP Framing There are three HDLC fr
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• The HDLC and PPP data-link prot
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Chapter 6. Network Switches In this
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Figure 6.1. Partial and full mesh m
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protocol. Figure 6.3 illustrates th
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All hosts can see the traffic that
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To get a better understanding of th
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Figure 6.5. A bridged LAN with span
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support a path discovery method. So
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or performance limitations, network
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network data encryption, WAN reacha
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The Impact of Switching on Traditio
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• Switch backplane—Also referre
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Switch Port Flow Control In full-du
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In the event that the primary trunk
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Figure 6.9. Layer 2 collision domai
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Figure 6.10. Multiport repeaters an
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Figure 6.11. Distributed and collap
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utilization performance. To calcula
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Ideally, the goal of all switch and
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Cut-through uses the same technolog
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VLANs A switch that supports VLAN p
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MAC Address-Based VLANs Another com
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Figure 6.13. Switches running indep
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The configuration layer uses the Ge
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Layer 2 infrastructures to operate
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need. This method not only allocate
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transmitting and receiving. Without
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ATM-specific applications would be
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ATM private-class switches are comp
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Because both the VPI and VCI are us
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environment. The goal is to have La
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Broadcast and Unknown Server The Br
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Figure 6.15. An LEC and its VCC rel
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ATM hosts are accomplished by estab
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• VLANs • Full-duplex switch po
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Chapter 7. Introduction to Cisco Ro
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The 4000 series routers come in a t
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series routers, this partition can
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need to crimp the CAT 5 strands fol
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Use the cable set to build the cabl
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Step 2. This command specifies whic
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AppleTalk FDDI IPX Token Ring VINES
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The IOS Command Line and Configurat
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disconnect Disconnect an existing n
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changes (user to privileged, for ex
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• Router(config)#hostname test-ro
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or • On 7x00 only, use: • •
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Null Null interface Tunnel Tunnel i
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Router(config)#ip rou? route routin
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Ctrl+P, up arrow Previous command i
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mop Copy from a MOP server (not ava
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Now let's see what is on the PCMCIA
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When copying any file, unless no pr
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Ethernet LANs with a dedicated T1 c
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Compiled Fri 03-Apr-98 07:00 by rna
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172.16.2.0 /25 172.16.2.128 /26 or
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Ridge-GW(config)# ip route 0.0.0.0
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In addition to their native protoco
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D - EIGRP, EX - EIGRP external, O -
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Configuring Dumb Terminal Service T
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Ctrl+Shift+6+X suspends a session).
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cornpops|Printer on Cisco termserve
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Concord-GW(config-if)#flowcontrol h
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The AUX port configuration for Ridg
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outer and enter the break sequence
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Setting the conf-reg Value in ROM M
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• Register setting 0x2010—Confi
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8. 9. Router#configure terminal 10.
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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Router#config t Enter configuration
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-#- ED --type----crc--- -seek--nlen
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to xmodem or TFTP (2600 only) an IO
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Mountain Standard Time (MST) -7 Pac
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eference time is BB0FC7AA.95E93186
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in production for a little while. T
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use debug mode often. When using th
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uucp UNIX-to-UNIX copy system IOS a
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Log Management Logs are useless unl
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IOS Authentication and Accounting I
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hostnames (which can be corrected w
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$telnet 192.160.56.5 Trying 192.160
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In this example, the authentication
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makes it easier to configure, becau
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define what authentication type sho
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Caution should be taken when using
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pairs (similar to those used to cre
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• Using rommon and disaster recov
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In the following section, we review
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Deciding to Use a Routing Protocol
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Now, here is the qualifier: Not eve
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If RIP was the routing protocol for
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Distance Vector Protocols All routi
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space) based on a power of 2. Class
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address space), but you would run i
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destination address that falls with
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the different IP address spaces int
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Weaknesses of Static Routing Static
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Today, RIP is considered by some to
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RIP 192.124.32.0 /24 192.124.35.1 3
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All routers on the network keep tra
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RIP's Value Today RIP is old, it's
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• Better reliability—OSPF route
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Figure 8.10. Single- and multi-area
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• Internal routers—These router
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to the backbone. In Figure 8.13, al
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Figure 8.14. OSPF router designatio
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oundary routers. They describe netw
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outer's point of view. The path con
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Autonomous Systems and Exterior Rou
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Figure 8.16. The IGP to ERP handoff
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Figure 8.17. The BGP finite state m
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EGPs have been increasing in popula
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Chapter 9. Advanced Cisco Router Co
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specified ACL number range. Table 9
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default, all traffic is denied. Onl
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asbr-a2#config t Enter configuratio
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trying to build ACLs with the comma
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trace Multicast trace IGMP log Log
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Tftp Trivial File Transfer Protocol
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access-list 100 permit tcp any 172.
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Table 9.5. AppleTalk ACL Filtering
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Figure 9.1. The AnyCo corporate App
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One word of caution: If you plan to
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You can also log hits on ports by a
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Table 9.8. Route-Map Operators for
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exists, a group identifier (which c
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hegel# With this configuration, bec
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NAT is commonly used in a fashion s
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The [prefix-length] or [netmask] se
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NAT's Shortcomings Although NAT is
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NOTE Administrators beware: Tunneli
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connects, the active key informatio
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encapsulation, framing, and line si
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asbr-a2(config-if)#ip address 172.1
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problem if you are provisioning ISD
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22:41:34: %LINK-3-UPDOWN: Interface
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POP mail request is made. Now let's
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leibniz(config-if)#backup interface
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When the primary link fails, the BR
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1.544Mbps. The actual transport lin
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the cost-effective and bandwidth-ef
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interface configuration subcommand
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it is possible to exchange packets
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interface serial0.2 point-to-point
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Figure 9.6. A multipoint FR example
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2. ATM encapsulation must be enable
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are commonly used in large-scale cl
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persephone(config)#interface atm 3/
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• The creation and application of
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Chapter 10. Configuring IP Routing
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After you have a list of requiremen
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Control commands: Displaying
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not active, it is quite common for
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Incoming update filter list for all
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When changing any IP routing behavi
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asbr-a1(config-if)#^Z asbr-a1# When
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For asbr-a2 to reach all the testne
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192.168.160.0/30 is subnetted, 1 su
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order to maintain computability wit
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Configuring Dynamic IGP and EGP IP
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passive-interface s1 By enabling th
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asbr-a1(config-router)#network 12.0
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To verify that the adjusted route m
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The command is a general routing p
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EIGRP, as I'm sure you have guessed
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No matter how the announcement entr
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Incoming update filter list for all
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is adjustable using the router con
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• IOS also supports various debu
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outers: • Backbone Routers—Thes
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process. The router would construct
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e1/1 192.168.9.0 fe0/0 192.168.0.0
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An alternative to this is to use th
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C 192.168.191.0/24 is directly conn
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Link State Age Interval is 00:20:00
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C 192.168.191.0/24 is directly conn
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to asbr-a1 was a remote office that
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interface Serial1 ip address 192.16
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which to exchange OSPF messages. Th
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OSPF Monitoring Commands Throughout
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• • • NOTE • will display
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Figure 10.4. AURP tunnel interfaces
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appletalk glean-packets hostname as
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For many users, the usefulness of B
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internal/Internet access router whe
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externally destined traffic arrives
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Routers asbr-a1/a2 and asbr-b1/b2 a
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BGP Reflectors An alternative to ha
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network 192.168.0.0 mask 255.255.25
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dynamic routing protocols are used
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Figure 10.8. An example network run
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Controlling Redistribution In some
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hostname ABR-a57 ! access-list 1 pe
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access-list 2 deny 10.0.1.0 access-
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Keep in mind that route-maps, li
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Chapter 11. Network Troubleshooting
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However, the most valuable tool of
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• Description of primary function
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of cable fault, different CSFSs are
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For Windows Systems, check out the
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command. On a Windows NT system, us
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#Do not change these variables logf
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# If any of the hosts fail to respo
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upgrade. So, when the time comes to
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throughput over time, instead of si
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protocol is the most prone to perfo
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NOTE When looking at network broadc
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NOTE Another common network error n
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and the physical ring segment that
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tolerances the frames, timing shift
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practical terms, this means that at
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etransmissions, however, usually ha
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4. Don't get lost in the big pictur
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• Link and services monitoring, n
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eports on network utilization, avai
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o Bandwidth utilization rates o Rat
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and improved management capabilitie
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After the supported SNMP version is
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Table 11.3. ASN.1 Keywords Used wit
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application-wide tags, which are us
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TestSequence ::= SEQUENCE { example
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The MIB-2 and RMON-MIB modules are
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iso.identfied-orgnaization.dod.inte
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accepted values are getRequest, get
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Spectrum is available in both UNIX
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Figure 11.8. Windows NT 4.0 SNMP Ag
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To access any of the NT SNMP agent
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The installation of the SNMP agent
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Figure 11.13. The Windows 95/98 Sel
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Figure 11.15. Locating the Windows
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Figure 11.17. The SNMP configuratio
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2. Scroll to Network Connectivity o
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sysLocation information, go to the
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example that just implements the ba
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protocol, service, and application
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RFC 1089 RFC 1147 RFC 1155 RFC 1157
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Appendix A. Binary Conversion Table
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