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http://www.pdc.kth.se/kth-krb/ http://www.cybersafe.com/ Using Old-Mode Authentication By default, the IOS uses AAA old-mode authentication. Under AAA old-mode, each dedicated and virtual line interface that requires authentication must be configured using the login command. Here is an example: local-AS#config t Enter configuration commands, one per line. End with CNTL/Z. local-AS(config)#line vty 0 4 local-AS(config-line)#login ? local Local password checking tacacs Use tacacs server for password checking local-AS(config-line)#login local local-AS(config-line)#exit local-AS(config)^Z local-AS# In the example above, you set up old-mode authentication on the VT ports on the router. You now need to create user accounts for each user who requires VT access to the router. This is the same process you used to create user accounts for the WidgetCo dial-in solution: local-AS#config t Enter configuration commands, one per line. End with CNTL/Z. local-AS(config)#username admin password apassword local-AS(config)#^Z local-AS# After the username is created, you can log in to the router using old-mode authentication:
$telnet 192.160.56.5 Trying 192.160.56.5… Connected to 192.160.56.5. Escape character is '^]'. User Access Verification Username: admin Password: local-AS> If you want to use a TACACS server, set up the interface and specify the address of the TACACS server: local-AS#config t Enter configuration commands, one per line. End with CNTL/Z. local-AS(config)#line AUX 0 local-AS(config-line)#login tacacs local-AS(config-line)#exit local-AS(config)#tacacs-server host 192.160.56.1 local-AS(config)#^Z local-AS# NOTE All user accounts and line passwords are in cleartext form unless password encryption is enabled (by using the global configuration command ). Also, there is no facility in the IOS for users to change their passwords, which substantially limits the security value of local user accounting. Using AAA New-Mode New-mode is enabled (along with authentication, accounting and authorization; hence, the name AAA) with the global configuration command :
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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
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Printer Access Protocol Printer Acc
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Figure 3.11. Novell (IPX) protocol
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The other nodes on the network that
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Figure 3.13. IPX datagram format.
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the cumulative information gleaned
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• Hop Count is the number of rout
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Upper Layer Protocols IPX is used t
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Msg.Add.Name Adds a unique name to
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Related RFCs RFC 1001 RFC 1002 RFC
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service enhancement or replacement
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Figure 4.1. The LLC interfaces in r
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it does not provide for error recov
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and smooth pattern flow enables MTL
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cabling, backbone length 800m Categ
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combination of light refraction and
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NOTE Cladding is the glass "shell"
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Ethernet The original Ethernet prot
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UTP telephone cabling infrastructur
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Since the introduction of the IEEE
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In the event that two Ethernet end-
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The 802.3 frame type used in Figure
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• Frame check sequence (4 bytes)
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• Physical layer signaling (PLS)
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cable segment length (for coaxial s
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transmission medium using BNC (Brit
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Figure 4.12. A basic 3-cable 10Base
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Figure 4.14. 10Base-T hub-to-hub in
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Figure 4.16. 10Base-T in a consulta
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• Support for full-duplex operati
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mechanisms, in terms of encoding an
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etween different PHY encoding imple
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100Base Ethernet) is based on the p
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The Gigabit PHY The Gigabit PHY con
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CSMA/CD is sensitive to operating r
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The main advantage of using FDR ove
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have to transmit against the priori
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• Ring timing maintenance—The A
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check the lobe cable. If the lobe t
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Token Ring addresses are expressed
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• Report Active Monitor Error (RA
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they first join the ring or in the
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Figure 4.22. The IBM type 1 MIC con
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FDDI Work on the Fiber Distributed
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However, all this comes at a cost,
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Figure 4.25. FDDI MAC data frame an
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topologies needed for the transmiss
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Chapter 5. WAN Internetworking Tech
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Placing a Call The functional model
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LATAs to provide local exchange ser
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The PSTN was originally designed fo
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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
Page 401 and 402: Compiled Fri 03-Apr-98 07:00 by rna
Page 403 and 404: 172.16.2.0 /25 172.16.2.128 /26 or
Page 405 and 406: Ridge-GW(config)# ip route 0.0.0.0
Page 407 and 408: In addition to their native protoco
Page 409 and 410: D - EIGRP, EX - EIGRP external, O -
Page 411 and 412: Configuring Dumb Terminal Service T
Page 413 and 414: Ctrl+Shift+6+X suspends a session).
Page 415 and 416: cornpops|Printer on Cisco termserve
Page 417 and 418: Concord-GW(config-if)#flowcontrol h
Page 419 and 420: The AUX port configuration for Ridg
Page 421 and 422: outer and enter the break sequence
Page 423 and 424: Setting the conf-reg Value in ROM M
Page 425 and 426: • Register setting 0x2010—Confi
Page 427 and 428: 8. 9. Router#configure terminal 10.
Page 429 and 430: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Page 431 and 432: Router#config t Enter configuration
Page 433 and 434: -#- ED --type----crc--- -seek--nlen
Page 435 and 436: to xmodem or TFTP (2600 only) an IO
Page 437 and 438: Mountain Standard Time (MST) -7 Pac
Page 439 and 440: eference time is BB0FC7AA.95E93186
Page 441 and 442: in production for a little while. T
Page 443 and 444: use debug mode often. When using th
Page 445 and 446: uucp UNIX-to-UNIX copy system IOS a
Page 447 and 448: Log Management Logs are useless unl
Page 449 and 450: IOS Authentication and Accounting I
Page 451: hostnames (which can be corrected w
Page 455 and 456: In this example, the authentication
Page 457 and 458: makes it easier to configure, becau
Page 459 and 460: define what authentication type sho
Page 461 and 462: Caution should be taken when using
Page 463 and 464: pairs (similar to those used to cre
Page 465 and 466: • Using rommon and disaster recov
Page 467 and 468: In the following section, we review
Page 469 and 470: Deciding to Use a Routing Protocol
Page 471 and 472: Now, here is the qualifier: Not eve
Page 473 and 474: If RIP was the routing protocol for
Page 475 and 476: Distance Vector Protocols All routi
Page 477 and 478: space) based on a power of 2. Class
Page 479 and 480: address space), but you would run i
Page 481 and 482: destination address that falls with
Page 483 and 484: the different IP address spaces int
Page 485 and 486: Weaknesses of Static Routing Static
Page 487 and 488: Today, RIP is considered by some to
Page 489 and 490: RIP 192.124.32.0 /24 192.124.35.1 3
Page 491 and 492: All routers on the network keep tra
Page 493 and 494: RIP's Value Today RIP is old, it's
Page 495 and 496: • Better reliability—OSPF route
Page 497 and 498: Figure 8.10. Single- and multi-area
Page 499 and 500: • Internal routers—These router
Page 501 and 502: 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
Page 513:
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
Page 524 and 525:
asbr-a2#config t Enter configuratio
Page 526 and 527:
trying to build ACLs with the comma
Page 528 and 529:
trace Multicast trace IGMP log Log
Page 530 and 531:
Tftp Trivial File Transfer Protocol
Page 532 and 533:
access-list 100 permit tcp any 172.
Page 534 and 535:
Table 9.5. AppleTalk ACL Filtering
Page 536 and 537:
Figure 9.1. The AnyCo corporate App
Page 538 and 539:
One word of caution: If you plan to
Page 540 and 541:
You can also log hits on ports by a
Page 542 and 543:
Table 9.8. Route-Map Operators for
Page 544 and 545:
exists, a group identifier (which c
Page 546 and 547:
hegel# With this configuration, bec
Page 548 and 549:
NAT is commonly used in a fashion s
Page 550 and 551:
The [prefix-length] or [netmask] se
Page 552 and 553:
NAT's Shortcomings Although NAT is
Page 554 and 555:
NOTE Administrators beware: Tunneli
Page 556 and 557:
connects, the active key informatio
Page 558 and 559:
encapsulation, framing, and line si
Page 560 and 561:
asbr-a2(config-if)#ip address 172.1
Page 562 and 563:
problem if you are provisioning ISD
Page 564 and 565:
22:41:34: %LINK-3-UPDOWN: Interface
Page 566 and 567:
POP mail request is made. Now let's
Page 568 and 569:
leibniz(config-if)#backup interface
Page 570 and 571:
When the primary link fails, the BR
Page 572 and 573:
1.544Mbps. The actual transport lin
Page 574 and 575:
the cost-effective and bandwidth-ef
Page 576 and 577:
interface configuration subcommand
Page 578 and 579:
it is possible to exchange packets
Page 580 and 581:
interface serial0.2 point-to-point
Page 582 and 583:
Figure 9.6. A multipoint FR example
Page 584 and 585:
2. ATM encapsulation must be enable
Page 586 and 587:
are commonly used in large-scale cl
Page 588 and 589:
persephone(config)#interface atm 3/
Page 590 and 591:
• The creation and application of
Page 592 and 593:
Chapter 10. Configuring IP Routing
Page 594 and 595:
After you have a list of requiremen
Page 596 and 597:
Control commands: Displaying
Page 598 and 599:
not active, it is quite common for
Page 600 and 601:
Incoming update filter list for all
Page 602 and 603:
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
Page 608 and 609:
192.168.160.0/30 is subnetted, 1 su
Page 610 and 611:
order to maintain computability wit
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Configuring Dynamic IGP and EGP IP
Page 614 and 615:
passive-interface s1 By enabling th
Page 616 and 617:
asbr-a1(config-router)#network 12.0
Page 618 and 619:
To verify that the adjusted route m
Page 620 and 621:
The command is a general routing p
Page 622 and 623:
EIGRP, as I'm sure you have guessed
Page 624 and 625:
No matter how the announcement entr
Page 626 and 627:
Incoming update filter list for all
Page 628 and 629:
is adjustable using the router con
Page 630 and 631:
• IOS also supports various debu
Page 632 and 633:
outers: • Backbone Routers—Thes
Page 634 and 635:
process. The router would construct
Page 636 and 637:
e1/1 192.168.9.0 fe0/0 192.168.0.0
Page 638 and 639:
An alternative to this is to use th
Page 640 and 641:
C 192.168.191.0/24 is directly conn
Page 642 and 643:
Link State Age Interval is 00:20:00
Page 644 and 645:
C 192.168.191.0/24 is directly conn
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to asbr-a1 was a remote office that
Page 648 and 649:
interface Serial1 ip address 192.16
Page 650 and 651:
which to exchange OSPF messages. Th
Page 652 and 653:
OSPF Monitoring Commands Throughout
Page 654 and 655:
• • • NOTE • will display
Page 656 and 657:
Figure 10.4. AURP tunnel interfaces
Page 658 and 659:
appletalk glean-packets hostname as
Page 660 and 661:
For many users, the usefulness of B
Page 662 and 663:
internal/Internet access router whe
Page 664 and 665:
externally destined traffic arrives
Page 666 and 667:
Routers asbr-a1/a2 and asbr-b1/b2 a
Page 668 and 669:
BGP Reflectors An alternative to ha
Page 670 and 671:
network 192.168.0.0 mask 255.255.25
Page 672 and 673:
dynamic routing protocols are used
Page 674 and 675:
Figure 10.8. An example network run
Page 676 and 677:
Controlling Redistribution In some
Page 678 and 679:
hostname ABR-a57 ! access-list 1 pe
Page 680 and 681:
access-list 2 deny 10.0.1.0 access-
Page 682 and 683:
Keep in mind that route-maps, li
Page 684 and 685:
Chapter 11. Network Troubleshooting
Page 686 and 687:
However, the most valuable tool of
Page 688 and 689:
• Description of primary function
Page 690 and 691:
of cable fault, different CSFSs are
Page 692 and 693:
For Windows Systems, check out the
Page 694 and 695:
command. On a Windows NT system, us
Page 696 and 697:
#Do not change these variables logf
Page 698 and 699:
# If any of the hosts fail to respo
Page 700 and 701:
upgrade. So, when the time comes to
Page 702 and 703:
throughput over time, instead of si
Page 704 and 705:
protocol is the most prone to perfo
Page 706 and 707:
NOTE When looking at network broadc
Page 708 and 709:
NOTE Another common network error n
Page 710 and 711:
and the physical ring segment that
Page 712 and 713:
tolerances the frames, timing shift
Page 714 and 715:
practical terms, this means that at
Page 716 and 717:
etransmissions, however, usually ha
Page 718 and 719:
4. Don't get lost in the big pictur
Page 720 and 721:
• Link and services monitoring, n
Page 722 and 723:
eports on network utilization, avai
Page 724 and 725:
o Bandwidth utilization rates o Rat
Page 726 and 727:
and improved management capabilitie
Page 728 and 729:
After the supported SNMP version is
Page 730 and 731:
Table 11.3. ASN.1 Keywords Used wit
Page 732 and 733:
application-wide tags, which are us
Page 734 and 735:
TestSequence ::= SEQUENCE { example
Page 736 and 737:
The MIB-2 and RMON-MIB modules are
Page 738 and 739:
iso.identfied-orgnaization.dod.inte
Page 740 and 741:
accepted values are getRequest, get
Page 742 and 743:
Spectrum is available in both UNIX
Page 744 and 745:
Figure 11.8. Windows NT 4.0 SNMP Ag
Page 746 and 747:
To access any of the NT SNMP agent
Page 748 and 749:
The installation of the SNMP agent
Page 750 and 751:
Figure 11.13. The Windows 95/98 Sel
Page 752 and 753:
Figure 11.15. Locating the Windows
Page 754 and 755:
Figure 11.17. The SNMP configuratio
Page 756 and 757:
2. Scroll to Network Connectivity o
Page 758 and 759:
sysLocation information, go to the
Page 760 and 761:
example that just implements the ba
Page 762 and 763:
protocol, service, and application
Page 764 and 765:
RFC 1089 RFC 1147 RFC 1155 RFC 1157
Page 766:
Appendix A. Binary Conversion Table
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