Pointto Multipoint Subinterface Configuration

R3(config) interface serial 0 0.134 multipoint R3(config-subif) ip address 172.16.134.3 255.255.255.0 R3(config-subif) frame-relay map ip 172.16.134.4 304 broadcast R3(config-subif) frame-relay map ip 172.16.134.1 301 broadcast R3(config) interface serial 0 0.134 multipoint R3(config-subif) ip address 172.16.134.3 255.255.255.0 R3(config-subif) frame-relay map ip 172.16.134.4 304 broadcast R3(config-subif) frame-relay map ip 172.16.134.1 301 broadcast

Configuring Root Guard

3 550(config) interface fastEthernet 0 3 3 55 0(config-if) spanning-tree guard root 2002, CiscoSystems, Inc. All rights reserved. When a change in the spanning-tree topology occurs, a new root bridge is sometimes selected. If you let spanning-tree defaults dictate the election of the root bridge, you may end up with a non-preferred switch, such as an access layer switch, performing the root bridge function. You can avoid this situation by configuring root guard the switches in your network. If...

Switched Port Analyzer SPAN

All rights reserved. Cisco CCIE Prep v1.0 Module 5-65 You can analyze network traffic passing through ports or VLANs by using SPAN to send a copy of the traffic to another port on the switch that has been connected to a SwitchProbe device or other Remote Monitoring (RMON) probe. SPAN mirrors received or sent (or both) traffic on a source port and received traffic on one or more source ports or source VLANs, to a destination port for analysis. For example, in the...

Inverse ARP should be disabled before bringing up the Frame Relay interface

All rights reserved. Once the interface is brought up with the no shutdown command, the Frame Relay switch will use Local Management Interface (LMI) to communicate the Data-Link Connection Identifier (DLCI) information to the router. Once the DLCIs have attained an active state, meaning that both sides of the connection are up and the Frame Relay switch has the correct Frame Relay route statements, Inverse Address Resolution Protocol (ARP) is performed to map the...

Advanced Configuration Options

This section will discuss BGP confederations and how to configure them. Confederations can be a solution to the iBGP full mesh problem R3(config) router R3(config-router) R3(config-router) R3(config-router) R3(config-router) R3(config-router) R3(config-router) R3(config-router) bgp confederation identifier 200 bgp confederation peers 65016 network 3.3.3.0 mask 255.255.255.0 neighbor 172.16.23.2 remote-as 100 neighbor 172.16.45.5 remote-as 65345 neighbor 172.16.70.4 remote-as 65345 neighbor...

Lesson Assessment Quiz

Q1) Which authentication method sends a clear-text password Q2) What authentication mechanism should be used if the destination device supports encrypted hashed messages, but cannot initiate authentication Q3) Which command changes how frequently MPPP calculates the need for additional B channels A) ppp timeout multilink link add Q4) The sent-username feature is used with which two authentication schemes Q5) What CHAP command should be used on a hub router that requires a different hostname be...

Load Sharing using STP Path Cost

Trunk Port 1 VLANs 2-4 (Path Cost 30) VLANs 8-10 (Path Cost 19) VLANs 8-10 (Path Cost 30) VLANs 2-4 (Path Cost 19) 2002, Cisco Systems, Inc. All rights reserved. You can configure parallel trunks to share VLAN traffic by setting different path costs on a trunk and associating the path costs with different sets of VLANs. The VLANs keep the traffic separate. Because no loops exist, STP does not disable the ports, and redundancy is maintained in the event of a lost link. In the figure above, Trunk...

EBGP Multihop

Use eBGP multihop when remote eBGP neighbor is not directly connected router(config-router) neighbor ip-address peer-group-name ebgp-multihop max-hop-count router(config-router) neighbor ip-address peer-group-name ebgp-multihop max-hop-count Usually, the two eBGP speakers are directly connected (for example, over a Wide Area Network (WAN) connection). Sometimes, they cannot be directly connected, such as the case when a router that does not use BGP is in between the two neighbors that wish to...

OSPF Virtual Link Configuration Example

All rights reservec In this example, Area 2 does not have a direct physical connection to the backbone (Area 0). To provide connectivity to the backbone, a virtual link must be configured between R6 and Rl. Area l will be the transit area, and Rl will be the entry point into Area 0. R6 will have a logical connection to the backbone through the transit area. Both sides of the virtual link must be configured using the neighboring Area Boarder Router's (ABR's) router ID,...

Backup Delay

Backup delay enable-delay never disable-delay never By default the secondary interface is immediately brought on primary link failure. 2001, Cisco Systems, Inc. All rights reserved. You can configure a value that defines how much time should elapse before a secondary line status changes after a primary line status change. This means that you can define two delays A delay that specifies the amount of time after the primary line goes down, but before the secondary line is activated A delay that...

Show Commands

Show commands are critical for identifying the configuration and status of ISDN. If you are experiencing problems with your BRI circuit, the first step is to perform a loopback test call. With a loopback call, the router dials the ISDN number of its own BRI interface. The call proceeds to the telco cloud, where the telco switches the call to the second BRI channel. The router now sees this call as an incoming call on the second channel. Therefore, the router verifies that it can both send and...

Hub router should be the DR no BDRs

All lights reserved. When the network type is set to non-broadcast, which is the default on NBMA networks, OSPF operates as if it were running in a broadcast multi-access environment, such as Ethernet. Therefore, a DR and BDR are elected for the NBMA network, and the DR originates the LinkState Advertisements (LSAs) for the network. If you are operating in a full mesh environment and the broadcast keyword is specified in your Frame Relay map statements, no other...

PPP Callback Client Configuration Callback Client requests callback

R4(config) username R1 password secret R4(config) interface briO O R4(config-if) ip address 172.16.14.1 255.255.255.252 R4(config-if) encapsulation ppp R4(config-if) dialer map ip 172.16.14.2 name R1 broadcast 5772222 R4(config-if) ppp authentication chap R4(config-if) ppp callback request Client configuration is very simple. You request the server to call you back using the command ppp callback request, as shown in the example above. 2001, Cisco Systems, Inc. All rights reserved.

Atm Pvc Auto Discovery on End Routers

R (config-if) ip address l0.l.l.l 255 ILMI uses the VPI VCI pair of 0 16 Inverse ARP is enabled by default when you create a PVC using the pvc command or when a PVC is auto-discovered using the command above 2OO2, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.O Module 4-3O You can use Integrated Local Management Interface (ILMI) to discover and configure the PVCs. ILMI uses what it gets from the adjacent switch. The router discovers the PVCs configured on the switch and configures...

Verifying VLAN Configuration

All rights reserved. Cisco CCIE Prep v1.0 Module 5-17 In much the same manner as VTP, VLAN problems usually arise when there is inconsistent VLAN information on the different switches in the network. You can use the show vlan command to display a list of all VLANs on each switch, including extended-range VLANs. The display includes VLAN status, ports, and configuration information. To view normal-range VLANs in the VLAN database (1 to 1005,) use the show VLAN...

Manual Summarization

Configurable on a per-interface basis in any router within network When summarization is configured on an interface, the router immediately creates a route pointing When the last specific route of the summary goes away, the summary is deleted The minimum metric of the specific routes is used as the metric of the summary route 2002, CiscoSystems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 6-57 EIGRP manual summarization is critical to large EIGRP networks. It limits the EIGRP query...

Configures interface as an OSPF demand circuit

All rights reserved. Cisco CCIE Prep v1.0 Module 7-46 To create an OSPF demand circuit, only one side of the connection is required to have the ip ospf demand-circuit command under its interface. If the other side of the link is capable of understanding the DC bit, it automatically negotiates the demand circuit capability in the hello packets sent between the neighbors. Table 6-24 < ip ospf demand-circuit > Command Table 6-24 < ip ospf demand-circuit > Command...

Backup Interface

A backup interface is an interface that stays idle until certain circumstances occur then it is activated. uscci. a m R4 (config-if) backup interfa R4(config-if) backup delay 1 r Time to Disconnect After Primary Is Active Specifies BRI 0 0 as a backup interface for serial 0 0 2001, Cisco Systems, Inc. All rights reserved. This example shows R4's Basic Rate Interface (BRI) interface being used to backup its primary link, which is the serial 0 0 interface The backup interface command is placed...

Regular Expression

Router(config-router) ip as-path access list < as-acl-num> permit deny < regular-expression> router(config-router) ip as-path access list < as-acl-num> permit deny < regular-expression> Receive routes from AS600 and directly attached AS access-list 1 permitA600 R1(config-router) ip as-path access-list 1 permitA600_ 0-9 * Receive routes from AS600 and directly attached AS access-list 1 permitA600 R1(config-router) ip as-path access-list 1 permitA600_ 0-9 * 2002, Cisco Systems,...

Troubleshooting VTP

Maximum VLANs supported locally 1OO5 MD5 digest Ox59 OxBA Ox92 OxA4 0x74 OxD5 Ox42 Ox29 Configuration last modified by 0.0.0.0 at 3-1-93 00 18 42 Local updater ID is 10.1.1.59 on interface Vl1 (lowest numbered VLAN interface found) Summary advertisements received 2 0 Subset advertisements received 0 Request advertisements received 0 Summary advertisements transmitted 11 < output omitted> 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 5-16 VTP problems usually...

Dampening

Router(config-router) bgp dampening half-life reuse suppress max-suppress router(config-router) bgp dampening route-map route-map-name routerft clear ip bgp dampening prefix mask Penalty Half-life time Suppress limit Suppressed Reuse limit History entry 2002, Cisco Systems, Inc. All rights res Border Gateway Protocol (BGP) sends a WITHDRAWN message to its peers when a prefix transitions from up to down. BGP sends an UPDATE message when the prefix transitions from down to up. This is commonly...

Management Interface Configuration

This section describes the initial configuration of the Catalyst 355O switch. For example, assigning the switch an IP address and default gateway. Configuring the Management Interface 3550(config-if) ip add 10.2.2.2 255.255.255.0 3550(config) ip default-gateway 10.1.1.1 s. Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 5-B Before you can configure the switch, you need connectivity to it via the console port. Make sure the terminal connected to the console port is configured as follows...

IBGP Basic Configuration

Router(config) router bgp < AS-number> router(config-router) neighbor ip-address peer R3(config-router) neighbor 172.16.70.4 remote-as R4(config-router) neighbor 172.16.70.3 remote-as 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 8-23 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 8-23 There are two primary commands required to configure an iBGP neighbor relationship. neighbor ip-address peer-group-name remote-as AS-number The first...

IBGP Advanced Configuration Synchronization Rule

Synchronization Rule Do not advertise a route if your IGP does not have it in its routing table. 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 8-26 The BGP rule of synchronization states that if an AS provides transit service to another AS, BGP should not advertise a route until all of the routers within the AS have learned about the route via an IGP. In other words, it states Do not advertise a route if the IGP does not have it in its routing table. This is an...

Verifying Interface Status

Interface IP-Address OK Method Status Protocol Serial 0 0 172.16.23.2 YES manual up up Serial0 0 is up, line protocol is up Hardware is DSCC4 Serial Internet address is 172.16.23.2 24 MTU 1500 bytes, BW 2048 Kbit, DLY 20000 usee, reliability 255 255, txload 1 255, rxload 1 255 Encapsulation FRAME-RELAY, loopback not set Keepalive set (10 sec) LMI enq sent 87, LMI stat recvd 88, LMI upd recvd 0, DTE LMI up LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0 LMI DLCI 102 3 LMI type is CISCO frame...

Conditional Advertisement and Route Filtering

Router(config-router) neighbor ip-address peer-group-name advertise-map route-map-namel non-exit-map route-map-name2 router(config-router) neighbor ip-address peer-group-name advertise-map route-map-namel non-exit-map route-map-name2 R3(config-router) neighbor 172.16.70.4 advertise-map ADVERTISE non-exist-map NONEXIST R3(config) access-list 3 permit 3.3.3.0 0.0.0.255 R3(config) access-list 30 permit 30.30.30.0 0.0.0.255 R3(config) route-map ADVERTISE permit 10 R3(config-route-map) match ip...

Deny Deny

R5(config-router) neighbor 172.16.56.6 route R5(config) access-list 1 deny 60.1.1.0 0.0.0 R5(config) access-list 1 deny 60.2.2.0 0.0.0 R5(config) access-list 1 permit any R5(config-route-map) match ip address 1 R5(config) route-map MYMAP permit 20 Denying in the route-map and denying with the conditional (ACL) statement is shown. With the deny deny form, the logic will follow the format execute the next route-map statement The logic of this form is a little difficult to understand. To make it a...

Verifying Eigrp Operation

This section describes how to verity EIGRP operation. This section describes how to verity EIGRP operation. show p eigrp neighbors Displays the neighbors router discovered by IP EIGRP show ip eigrp topology Displays the IP EIGRP topology show ip route eigrp Displays current EIGRP entries - in the routing table show ip protocols Displays the parameters and show ip eigrp traffic Displays the number of IP EIGRP 002, CiscoSystems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 6-63 The show...

OSPF Configuration in a Broadcast Multi Access Topology

This section discusses Open Shortest Path First (OSPF) operation and configuration in a broadcast multi-access environment such as Ethernet or Token Ring. interface EthernetO ip address 10.64.0.1 2 55.255.255.0 router ospf 1 network 10.0.0.0 0.255.255.255 area 0 Can assign network or interface address- interface EthernetO ip address 1O.64.O.2 2 55.255.255.0 ip address 172.16.14.4 255.255.255.0 router ospf 50 network 172.16.14.4 0.0.0.0 area 0 network 10.64.0.2 0.0.0.0 area 0 2002, Cisco...

Removing Private AS Numbers

Router(config-router) neighbor ip-addressl peer-group-name remove-private-as Private AS numbers should not be leaked into the Internet To overcome this limitation, the BGP spec specifies the use of private AS numbers, which range from 64152 to 65535. Your Internet Service Provider (ISP) can assign you a private AS, but that AS should not be advertised to the Internet community (other ISPs). To remove the private AS from updates, your ISP would issue the following command on peer statements to...

Q Tunneling

All rights reserved. 2002, CiscoSystems, Inc. All rights reserved. Business customers of service providers often have specific requirements for VLAN IDs and the number of VLANs to be supported. The VLAN ranges required by different customers in the same service-provider network might overlap, and traffic of customers through the infrastructure might be mixed. Assigning a unique range of VLAN IDs to each customer would restrict customer configurations and could easily...

Troubleshooting Layer 2 Problems

SerialO O is up, line protocol is down Hardware is DSCC4 Serial Internet address is 172.16.23.2 24 MTU 15OO bytes, BW 2O48 Kbit, DLY 2OOOO usee, reliability 255 255, txload 1 255, rxload 1 255 Encapsulation FRAME-RELAY, loopback not set Keepalive set (10 sec) LMI enq sent 324, LMI stat recvd 131, LMI upd recvd 0, DTE LMI down LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0 LMI DLCI 0 LMI type is ANSI Annex D frame relay DTE FR SVC disabled, LAPF state down Broadcast queue 0 64, broadcasts sent...

Use subinterfaces to avoid split horizon issues

All rights reservec 2002, Cisco Systems, Inc. All rights reservec Subinterfaces provide a mechanism for supporting partially meshed Frame Relay networks. Most protocols assume transitivity on a logical network that is, if R4 can talk to R3, and R3 can talk to Rl, then R4 should be able to talk to R1 directly. Transitivity is true on Local Area Networks (LANs), but not on Frame Relay networks, unless R4 is directly connected to Rl. Subinterfaces address the limitations...

Basic Eigrp Configuration

All rights reserved. Cisco CCIE Prep v1.0 Module 6-53 Configuring EIGRP calls for the definition of an Autonomous System (AS). By definition, an AS is a set of routers under a single administrative technical authority. Like IGRP, EIGRP uses the concept of autonomous systems to separate routing processes. Having a registered AS when configuring EIGRP is not required, nor does EIGRP use the AS for routing decision. The following two-step process can be used to configure...

Peer Groups

A BGP peer group is a group of BGP neighbors that share the same update policies. Update policies are usually set by route maps, distribution lists, and filter lists. Instead of defining the same policies for each individual neighbor, you define a peer group name and assign policies to the peer group. Members of a peer group inherit all of the configuration options of the peer group. Peer group members can also be configured to override configuration options if the options do not affect...

PAP One Way Cont

R4(config) interface bri0 0 R4(config-if) encapsulation ppp . R4(config-if)ftf p authentication pap callin Credentials Used to Authenticate to Router 2001, Cisco Systems, Inc. All rights reserved. Examine the configuration for R4 (the client). This router needs to produce identification in order to gain access to resources beyond R1 (the server). PAP requires Point-to-Point Protocol (PPP) encapsulation, which is specified first. Next, issue the command ppp authentication pap callin, which...

VTP Overview

Client Mode Transparent Mode Client Mode 2002, Cisco Systems, Inc. All rights reservec VTP is a Layer 2 messaging protocol that maintains VLAN configuration consistency by managing the addition, deletion, and renaming of VLANs on a network-wide basis. VTP minimizes misconfigurations and configuration inconsistencies that can cause several problems, such as duplicate VLAN names, incorrect VLAN-type specifications, and security violations. Before you create VLANs, you must decide whether to use...

Configuring a Default Route

All lights reserved. Defines a default route that is pointed to R4 2002, Cisco Systems, Inc. All lights reserved. NSSA default-information originate command will allow Type 3 4 LSAs into the area and define a default route that is pointed to the ASBR, R4. This command can be preceded by the no-redistribution to stop Type 7 LSAs from being propagated. Table 6-14 < area < area-id> nssa default-information-originate > Command Table 6-14 < area < area-id>...

OSPF Operation in an NBMA Topology

OSPF can be configured in any networks Broadcast - Designed for full mesh NBMA environments Point-to-point - Default network type for point-to-point interfaces, this includes point-to-point subinterfaces. Point-to-multipoint - Designed for a hub and spoke topology in which the hub has a separate point-to-point subinterface to each spoke. Non-broadcast -Default network type for NBMA networks 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 7-11 Special care should be...

Debugging ATM Cont

All rights reservec The following command will assist you in showing ILMI events. ilmi Show ILMI events Sample output (after a shutdown-no shutdown on the main ATM interface) for this command is shown here 20 44 52 ILMI(ATMl 0) Response received for request 2042 20 44 52 ILMI Continuing Getnext processing 20 44 52 ILMI Delivering GetNext response to Client atmfVccEntry.l3.0.l.l02-l 20 44 52 ILMI(ATMl 0) Sending out Request 2043 20 44 52 ILMI(ATMl 0) Response received...

Debugging ISDN Layer

The ISDN switch cannot assign the requested Terminal Endpoint Identifier (TEI). If this message has AI 127, then the ISDN switch has no TEIs available. It is usually followed by another IDREQ from the router. Reset the BRI interface using clear interface bri number or shut no shut on the interface. If AI 127, then contact the telco provider. The ISDN switch has removed the TEI (ID) from the connection. The routermust discard all exiting communication using that TEI. Check to see if a new TEI is...

Route Aggregation

Aggregate addresses allow summary advertisements Syntax router(config-router) aggregate-address address mask 172.16.134.0 24 150.10.0.0 16 AS 100 150.0.0.0 8 150.10.0.0 16 AS 300 1 50.40.0.0 16 AS 200 150.0.0.0 8 150.10.0.0 16 AS 300 1 50.40.0.0 16 AS 200 aggregate-address 150.0.0.0 255.0.0.0 2002, Cisco Systems, Inc. All rights reserved. 2002, Cisco Systems, Inc. All rights reserved. In the scenario, two different AS systems are sending class B networks to a 3rd AS. R1 is advertising the...

Configuring Uplink Fast

3550 (config) spanning-tree uplinkfast 2002, CiscoSystems, Inc. All rights reserved. If a switch looses connectivity, it begins using the alternate paths as soon as the spanning tree selects a new root port. By enabling UplinkFast, you can accelerate the choice of a new root port when a link or switch fails or when the spanning tree reconfigures itself. The root port transitions to the forwarding state immediately without going through the listening and learning states, as it would with the...

Configuring PVC Traffic Parameters

This section covers configuring the various PVC traffic parameters. This section covers configuring the various PVC traffic parameters. - QoS low tolerance for cell loss and cell delay VBR-RT Variable Bit Rate, Real Time - Traffic parameters PCR SCR MBS CDVT - QoS low tolerance for cell loss and cell delay VBR-NRT Variable Bit Rate, Non-Real Time - Traffic parameters PCR SCR MBS CDVT - QoS low tolerance for cell loss high tolerance for cell - Traffic parameters PCR MCR CDVT - QoS low tolerance...

Interface Ranges

When using the interface range global configuration command, note these guidelines Valid entries for port-range vlan vlan-ID - vlan-ID, where VLAN ID is from 1 to 4094 fastethernet slot ffrst port - last port , where slot is 0 gigabitethernet slot ffrsf port - last port , where slot is 0 port-channel port-channel-number - port-channel-number, where port-channel-number is from 1 to 64 You must add a space between the interface numbers and the hyphen when using the interface range command. For...

Connecting a Non Backbone Area Through a Stub Area

Generic Routing Encapsulation (GRE) allows you to connect a discontiguous area to the backbone through a stub area * GRE will cause extra packet overhead due to tunnel header information 2002, Cisco Systems, Inc. All rights reserved. In this example, Area 1 has been configured as a stub area. This prevents the use of a virtual link, as virtual links are not allowed across stub areas. To provide Area 2 with connectivity to the backbone area, you could alternatively build a Generic Routing...

Aggregate With the asset Argument

Aggregate addresses allow summary advertisements Syntax router(config-router) aggregate-address address mask summary-only as-set 172.16.134.0 24 AS 300 300(100,400 AS 200 172.16.134.0 24 AS 300 300(100,400 AS 200 2002, Cisco Systems, Inc. All rights reserved. The form of the aggregate that advertises the aggregate while retaining the AS path information is shown. Using the as-set keyword creates an aggregate entry using the same rules that the command follows without this keyword, but the path...

Multiplier is the number specified by the variance command

All rights reserved. Cisco CCIE Prep v1.0 Module 6-60 EIGRP also has the capability to use unequal-cost load balancing in the same manner as IGRP. The router uses variance as a multiplier in choosing the upper boundary of path with the greatest metric. Configuring EIGRP unequal-cost load balancing is a three-step process Step 1 Configure the bandwidth on both sides of all the interfaces involved in the load-sharing group. Use the bandwidth xxkbps command to accomplish...

Configuring the AAL and Encapsulation Type

This section covers configuring the AAL and encapsulation type options. This section covers configuring the AAL and encapsulation type options. SEAL Simple and Efficient Adaptation 2002, Cisco Systems, Inc. All rights reserve AAL1, a connection-oriented service, is suitable for handling circuit-emulation applications, such as voice and video conferencing. Circuit-emulation service also accommodates the attachment of equipment currently using leased lines to an ATM backbone network. AAL1...

Troubleshooting a Flapping ISDN Link in OSPF

Fast idle timer (20 sees) Wait for earrier (30 sees). Re-enable (2 sees) Dialer state is data link layer up Dial reason ip (s 172.16.14.4, d 224.0.0.5) Numerous changes to the network topology can cause DDR links to be frequently connected 2002, Cisco Systems, Inc. All rights res When an Integrated Services Digital Network (ISDN) link is configured as an OSPF demand circuit, OSPF hellos are suppressed and periodic LSA refreshes are not flooded over the link. These packets...

Reason 3 Redistribution from a Classful Routing Protocol

Route redistribution can cause frequent DDR connections 2OO2, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.O Module 7-83 Reason 3 Redistribution from a classful routing protocol is being performed on one of the routers that connect to the OSPF demand circuit. This is probably the most common reason that ISDN links configured as OSPF demand circuits still flap. It is also the hardest to troubleshoot and fix. In the example above, the ISDN link between R4 and R1 is 172.16.14.0 24...

External Route Summarization

R4(config-router) summary-address 192.168.0.0 255.255.0.0 2002, Cisco Systems, Inc. All lights reserved. To configure manual route summarization on an ASBR to summarize external routes, use the summary-address command. This command instructs the ASBR to summarize external routes before injecting them into the OSPF domain. Table 6-17 < summary-address > Command Table 6-17 < summary-address > Command Summary address designated for a range of external routes. Performed in router...

Using Dialer Interfaces for Backup

R4(config) interface bri 0 0 R4(config-if) no ip address R4(config-if) encapsulation ppp R4(config-if) dialer pool-member 1 R4(config) dialer-list 1 protocol ip permit R4(config) interface dialer 1 R4(config-if) ip address 172.16.14.1 255.255.255.252 R4(config-if) encapsulation ppp R4(config-if) dialer string 8140010 R4(config-if) dialer remote-name R1 R4(config-if) dialer pool 1 R4(config-if) dialer-group 1 R4(config) dialer-list 2 protocol ip list 102 R4(config) access-list 102 permit tcp any...

Controlling Attributes with Route Maps

* Route maps are the preferred choice for filtering and attribute manipulation router(config-router) neighbor ip-address j peer-group-name route-map route-map-name in out * You can use route maps in all of the following BGP related commands. aggregate-address address mask advertise-map route-map-name aggregate-address address mask as-set route-map-name aggregate-address address mask attribute-map route-map-name aggregate-address address mask route-map route-map-name aggregate-address address...

Demand Circuit

Stops the LSA refreshes that occur every Can be verified through the show ip 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 7-66 The periodic Link-State Advertisement (LSA) refreshes that take place every 30 minutes in OSPF do not occur over the demand circuit. When the demand circuit is established, a unique option bit (the DC bit) is exchanged between the neighboring routers. If the two routers negotiate the Direct Current (DC) bit successfully, they will make a...

Using Dialer Interfaces for DDR

R4(config) interface bri 0 0 R4(config-if) no ip address R4(config-if) encapsulation ppp R4(config-if) dialer pool-member 1 R4(config) dialer-list 1 protocol ip permit R4(config) interface dialer 1 R4(config-if) ip address 172.16.14.1 2 55.255.255.252 R4(config-if) encapsulation ppp R4(config-if) dialer string 8140010 R4(config-if) dialer remote-name R1 R4(config-if) dialer pool 1 R4(config-if) dialer-group 1 R4(config) dialer-list 2 protocol ip list 102 R4(config) access-list 102 permit tcp...

Verifying Dialer Maps

Displays all configured dialer map statements (static and dynamic) 2001, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 3-83 To display configured dialer maps, use the show dialer map command in EXEC mode. The following table describes the significant fields in this output. Table 3-2 Interpreting < show dialer map> Output Table 3-2 Interpreting < show dialer map> Output This is a statically configured dialer map to call the specified protocol address The interface...

Different Types of Switch Ports

com Access Ports belong to and carry the traffic of only one VLAN Trunk Ports carry the traffic of multiple VLANs and by default is a member of all VLANs in the VLAN database. Both ISL and 802.1Q trunk ports are supported Tunnel Ports designed for service providers who carry traffic of multiple customers across their networks and are required to maintain the VLAN and Layer 2 protocol configurations of each customer without impacting the traffic of other customers. Both 802.1Q tunneling and...

Verifying ATM Cont

All rights reserved. Cisco CCIE Prep v1.0 Module 4-73 The show atm map command is very useful for checking any kind of virtual connection that transports higher-level protocols. Whenever you lose or cannot achieve connectivity, this is one of the first commands to use to check the configuration. show atm pvc, as well as the related commands, show atm svc, show atm vc, show atm vp, give information on the connections you have configured. It is a good idea to use them...

Viewing the Link State Database

The show ip ospf database command displays the link-state database. The link-state database contains a listing of all the LSAs that a router knows about. This command is useful in verifying that OSPF is learning about a network, but is not putting it into the routing table for one reason or another. This command is also useful in verifying the operation of an OSPF demand circuit, by looking for LSAs marked as DoNotAge (DNA). Table 6-27 < show ip ospf database > Command Table 6-27 < show...

Tuning EIGRP

HffTMTITl III II III II III III II III IIIII III II III IIIII III II III III II III II III III II CiGco.com ip hello-interval eigrp - use this interface command to change the hello timer ip hold-time eigrp - use this command to change the EIGRP hold timer for routes received by this interface metric weights - allows you to set the weight of the EIGRP metric distance - used to change the administrative distance of routes received from a neighbor delay - specifies the delay of an interface in...

Course Roadmap

All rights reserved. The schedule reflects the recommended structure for this course. This structure allows enough time for the instructor to present the course information and for you to work through the laboratory exercises. The exact timing of the subject materials and labs depends on the pace of your specific class.

Aggregating While Suppressing Individual Routes

Use the suppress-map keyword to suppress specified routes router(config-router) aggregate-address address mask suppress-map route-map router(config-router) aggregate-address address mask suppress-map route-map 2002, Cisco Systems, Inc. All lights reserved. Cisco CCIE Prep v1.0 Module 8-75 2002, Cisco Systems, Inc. All lights reserved. Cisco CCIE Prep v1.0 Module 8-75 The form of the aggregate command that advertises the aggregate while suppressing only the more specific routes indicated by a...

Examples

Only Allow Networks Locally Originating from AS For example, you want an AS to advertise only routes it locally originates. In another example, you want R5 to advertise only its locally originated routes. Apply the following outbound filter on R5. Only Allow Networks Originating from AS 600 to Enter R1 You want R1 to receive only the routes originated from AS 600 (and no Internet routes). You can apply an inbound access list on R1 as follows ip as-path access-list 1 permit 600 Only Allow...

EIGRP Split Horizon

Example For Split Horizon Cisco

EIGRP actually runs its own version of split horizon for all of the protocols that it supports IP, Internetwork Packet Exchange (IPX), and Appletalk. Frame Relay Technologies and split horizon are a routing technique used with classful routing protocols in which routing updates are prevented from being advertised out the same interface from which they were learned. Split horizon issues are most prevalent in NBMA hub and spoke networks. To remedy this, split horizon is disabled by default on...

PPP Callback Additional Commands

Rl(config-if) dialer enable-timeout 5 Modifies the amount of time a callback server waits to call back a client Configures the number of interesting outgoing packets a client will queue while waiting for a callback from the server 2001, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 3-52 By default, the callback server will wait 15 seconds before it attempts to initiate a callback to the client. You can modify this timer with the dialer enable-timeout command. To set it to...

Cost based on bandwidth parameter on Cisco devices

All rights reserved. Cisco CCIE Prep v1.0 Module 7-19 Cisco's OSPF default cost assignment is based on the bandwidth of the link. Other vendors might use a different mechanism to assign OSPF cost to a link, so you may have to manually set the cost associated with a link in some scenarios. OSPF requires that all interfaces connected to a link agree on the link's cost. By default, Cisco routers calculate the cost of a link using the following formula. Reference...

Multilink PPP cont

Activates the interface for Multilink PPP operation R4(config-if) dialer load-threshold 128 outbound Allows additional B-Channels to be added to the Multilink PPP bundle once the current bandwidth utilization reaches 50 in the outbound direction 2001, Cisco Systems, Inc. All rights rieserived. Cisco CCIE Prep v1.0 Module 3-40 The command ppp multilink activates the interface for MPPP operation and allows negotiation of Multilink PPP at connect time, thus establishing a single-channel MPPP...

Four ways to affect DRBDR election

Manually configure IP OSPF priority 2. Manually configure router ID 3. Highest IP address on a loopback interface 4. Highest IP address on a physical interface 2002, Cisco Systems, Inc. All rights reserved. OSPF uses the highest Internet Protocol (IP) address configured on an interface as its router ID. If the interface associated with this IP address is ever brought down, or if the address is removed, the OSPF process must recalculate a new router ID and resend all of its routing information...

How Does CHAP Work

All rights reserved. This scenario examines exactly how CHAP authentication works from the perspective of R4, 1. When Rl receives the call, it challenges R4 for authentication. By default, the hostname of the router is used to identify itself. If the ppp chap hostname name command is configured, a router uses this name in place of its hostname to identify itself. In this example, the challenge is labeled as it is coming from Rl. 2. R4 receives Rl's challenge and looks...

Routing Over ATM

In order for a PVC or SVC to pass routing updates, you must configure the PVC or SVC to pass broadcast traffic. You can do this either per destination on the PVC or SVC by using the broadcast keyword at the end of an ATM mapping statement, or globally for the entire PVC or SVC using the broadcast command. 2002, CiscoSystems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 4-55 Routing protocols such as Open Shortest Path First (OSPF) and Enhanced Interior Gateway Routing Protocol (EIGRP)...

EIGRP Summarization Automatic

Purpose Smaller routing tables, smaller updates, query boundary - On major network boundaries, subnetworks are summarized to a single classful (major) network Autosummarization is turned on by default 2002, Cisco Systems, Inc. All rights reservec By default, EIGRP performs auto summarization in two situations Auto summarization will occur at the major class boundary during redistribution from EIGRP into a classful routing protocol such as IGRP or RIP. This type of summarization cannot be...

Debugging PPP

no debug ppp packet negotiation error authentication compression cbcp no debug ppp packet negotiation error authentication compression cbcp Causes the debug ppp command to display PPP packets being sent and received. (This command displays low-level packet dumps.) Causes the debug ppp command to display PPP packets transmitted during PPP startup, where PPP options are negotiated Causes the debug ppp command to display protocol errors and error statistics associated with PPP connection...

Viewing the Routing Table

Codes C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP, D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area, N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP, i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route O E2 200.1.1.0 24 110 20 via 2.2.2.2, 00 22 53, EthernetO O E1...

OSPF over NBMA Topology Summary

Partial mesh (hub and spoke), using subinterfaces 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 7-28 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 7-28 This table provides a concise comparison of the different modes of operation for OSPF over NBMA topologies.

Fallback Bridging

Fallback Bridging Network Diagram

This section describes how to configure fallback bridging (VLAN bridging) on your switch. With fallback bridging, you can forward non-IP packets that the switch does not route between VLAN bridge domains and routed ports. To use this feature, you must have the enhanced multilayer software (EMI) image installed on your switch. With fallback bridging, the switch bridges together two or more VLANs or routed ports, essentially connecting multiple VLANs within one bridge domain. Fallback bridging...

Dialer Watch Configuration

Dialer watch configuration is built by having an interface monitor a specified route or set of routes. R4(config-if) ip addr 172.16.14.1 2 55.255.255.252 R4(config-if) dialer watch-disable 15 R4(config-if) dialer watch-group 10 R4(config) dialer watch-list 10 ip 172.16.10.0 2 55.255.255.0 R4(config) dialer-list 1 protocol ip list 101 R4(config) access-list 101 remark Define Interesting Traffic R4(config) access-list 101 deny ospf any any R4(config) access-list 101 permit ip any any...

Layer 2 Protocol Tunneling

Cisco Switch Virtual Interfaces Svi

2002, Cisco Systems, VLANSsI to 200 2002, Cisco Systems, VLANSsI to 200 Customers that have different sites connected across a service-provider network and want to scale this topology into one large layer 2 domain need to run various Layer 2 protocols between sites. For example, STP must run properly, and every VLAN should build a proper spanning tree that includes the local site and all remote sites across the service-provider infrastructure. Cisco Discovery Protocol (CDP) must discover...

Configuring OSPF Authentication

Router (config-router) area 0 authentication router (config-if) ip ospf authentication-key auth593 2DD2, Cisco Systems, Inc. All rights reserved. Plain text authentication allows a key (password) to be configured per area. All routers in the same area that want to participate in OSPF will have to be configured with the same key. Plain text authentication sends the authentication key itself in plain text over the wire. The drawback of this method is that it is vulnerable to eavesdropping...