CCIE

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...

What is ATM

All rights reservec Asynchronous Transfer Mode (ATM) is an International Telecommunication Union Telecommunication Standardization Sector (ITU-T) standard for cell relay wherein routers convey information for multiple service types, such as voice, video, or data, in small, fixed-size cells. ATM networks are connection oriented. ATM is a cell-switching and multiplexing technology that combines the benefits of circuit switching (guaranteed capacity and constant...

Layer 2 Protocol Tunneling

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...

Learner Introductions

This is the point in the course where you introduce yourself. This is the point in the course where you introduce yourself. Your name Your company Skills and knowledge Brief history Objective Your name Your company Skills and knowledge Brief history Objective 2002, CiscoSystems, Inc. All rights reserved. Prepare to share the following information A profile of your experience Are there any subject areas you would like to concentrate on This section covers lab registration. This section covers...

Configuring the AAL and Encapsulation Type

R7(config-if-atm-vc) encapsulation aal5ciscoppp Cisco PPP over AAL5 Encapsulation aal5nlpid AAL5+NLPID Encapsulation aal5snap AAL5+LLC SNAP Encapsulation R7(config-if-atm-vc) encapsulation aal5ciscoppp Cisco PPP over AAL5 Encapsulation aal5nlpid AAL5+NLPID Encapsulation aal5snap AAL5+LLC SNAP Encapsulation 2002, Cisco Systems, Inc. All rights reservec Use the aal5mux encapsulation option to dedicate the specified virtual circuit to a single protocol use the aal5snap encapsulation option to...

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...

Configuring the Idle Timeout

R4(config-if) dialer idle-timeout 60 Used to specify the amount of time the line can sit idle before it is disconnected Used to drop the connection more quickly if another call is waiting to use the DDR interface 2001, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 3-14 To specify the idle time before the line is disconnected, use the dialer idle-timeout command in interface configuration mode. Remember the dialer idle-timeout command is based on interesting traffic...

Fallback Bridging

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...

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...

Can be used with hub and spoke topology

All rights reserved. To avoid the headaches with non-broadcast and broadcast modes, the point-to-multipoint network type is available. An OSPF point-to-multipoint network is seen as one or more numbered point-to-point interfaces. As with the non-broadcast and broadcast modes, the NBMA cloud is seen as one IP subnet. The main advantage to using the point-to-multipoint network type is that it does not require the use of a DR BDR. OSPF point-to-multipoint networks avoid...

Ciscos Certification Track

This section lists the certification requirements of this course. This section lists the certification requirements of this course. CCIE (Cisco Certified Internetwork Expert) CCIE (Cisco Certified Internetwork Expert) CCDP (Cisco Certified Design Professional) CCNP (Cisco Certified Network Professional) * Routing and Switching Support CCIP (Cisco Certified Internetwork Professional) CCNA (Cisco Certified Network Associate) * Routing and Switching Support CCDA (Cisco Certified Design Associate)...

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...

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...

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...

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...

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,...

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...

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...

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...

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...

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...

Configuring PVCs Required and Optional Tasks

Mapping a Protocol Address to a PVC Optional Tasks Configuring the AAL and Encapsulation Type Configuring PVC Traffic Parameters 2003, Cisco Systems, Inc. All rights reserved. Cisco CCIE Routing and Switching e-Prep v2.1 Module 1-6 To configure a PVC, perform the following tasks. The first two tasks are required the other tasks are optional Mapping a Protocol Address to a PVC (Required) Configuring the ATM Adaptation Layer (AAL) and Encapsulation Type (Optional) Configuring PVC Traffic...

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...

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...

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...

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...

Ether Channel Overview

All rights reservec An EtherChannel consists of individual Fast Ethernet or Gigabit Ethernet links bundled into a single logical link. The EtherChannel provides full-duplex bandwidth up to 800 Mbps (Fast EtherChannel) or 8 Gbps (Gigabit EtherChannel) between your switch and another switch or host. Each EtherChannel can consist of up to eight compatibly configured Ethernet interfaces. All interfaces in each EtherChannel must be the same speed, and all must be...

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...

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...

Lesson Assessment Quiz

Ql) Which show command is useful to view the ISDN information for layers 1, 2 and 3 Q2) Which show command can be used to show detailed information about calls in progress Q3) What show command is useful for the verification of DDR setup Q4) Which ISDN debug command displays data link layer information Q5) Which ISDN debug command is most appropriate for verifying DDR operation

Configuring Backbone Fast

BackboneFast Receipt of inferior BPDUs triggers root link query PDU BackboneFast Receipt of inferior BPDUs triggers root link query PDU 3 550(config) apanning-tree backbonefaat 2002. Cisco Systems. Inc. All rights reserved. BackboneFast detects indirect failures in the core of the backbone. BackboneFast is a complementary technology to the UplinkFast feature, which responds to failures on links directly connected to access switches. BackboneFast optimizes the maximum-age timer, which determines...

Timers can be manually adjusted through the ip ospf hellointerval and ip ospf deadinterval commands

All rights reserved. Cisco CCIE Prep v1.0 Module 7-21 OSPF requires these intervals to be exactly the same between two routers in order for the routers to form a neighbor adjacency. If either of these intervals is different, the routers will not become neighbors on a particular segment. Changing the OSPF network type with the ip ospf network command affects these intervals. Here is a list of the default intervals for the different network types. Broadcast Hello time...

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...

Verifying Active Calls

Call Calling Type Number Units Currency 2001, Cisco Systems, Inc. All rights reserved. The show isdn active command displays information about the current call. This command can be used to verify that PPP callback was successfully completed. If callback is successful, show isdn active will show the call as incoming on the callback client and outgoing on the callback server. Dial String Successes Failures Last called Last status 0 incoming call(s) have been screened. Idle timer (12 0 secs), Fast...

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...

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...

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...

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...

Verifying PVC Status

PVC Statistics for interface SerialO O (Frame Relay DTE) DLCI 2 03, DLCI USAGE LOCAL, PVC STATUS ACTIVE, INTERFACE Serial0 0 input pkts 4 5 ou t bytes 0 in BECN pkts 0 in DE pkts 0 out bcast pkts 0 output pkts 0 dropped pkts 0 out FECN pkts 0 out DE pkts 0 out bcast bytes 0 in bytes 13230 in FECN pkts 0 out BECN pkts 0 pvc create time 01 46 39, last time pvc status changed Indicates the DLCI number associated with the PVC Indicates the interface on which the PVC was learned 2002, Cisco Systems,...

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...

Clearing a BGP Connection

The clear ip bgp command is used to reset a BGP connection. These BGP connections can be reset based on 2002, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0 Module 8-34 clear ip bgp * address soft in out The clear ip bgp command is used to reset a BGP connection. BGP connections can be reset based on Neighbor's AS number Peer group name You must reset your BGP connections when any of the following have been modified or added to BGP route map BGP distribute list BGP weight BGP...

Each pointtopoint subinterface is treated as a separate subnet

All rights reserved. Point-to-point subinterfaces allow a Cisco router to treat each Permanent Virtual Circuit (PVC) as a separate IP subnet. By doing this, the Non-Broadcast Multi-Access (NBMA) characteristics of a Frame Relay network can be avoided. Point-to-point subinterfaces are also used to resolve split horizon issues. By default, split horizon is disabled on all physical interfaces and point-to-multipoint subinterfaces configured for Frame Relay. This is...

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...

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...

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...

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...

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...

What is EIGRP

Enhanced Interior Gateway Routing Protocol (EIGRP) is a classless routing protocol that directly interfaces to Internet Protocol (IP) as protocol 88. * Multiple network-layer protocols 2002, Cisco Systems, Inc. All rights reservec EIGRP uses the multicast address of 224.0.0.10 for 'hellos' and routing updates instead of an all hosts broadcast like Routing Information Protocol (RIP) uses. EIGRP also employs a system of hello and hold timers to maintain neighbors. Aside from the initial routing...

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...

Configuring Layer 3 Ether Channels

3550(config) interface port-channel 2 3 55 0(config-if) ip add 172.16.1.1 255.255.0.0 To configure Layer 3 EtherChannels, you must first create the port-channel logical interface and then put the Ethernet interfaces into the port-channel. 2002, CiscoSystems, Inc. All rights reserved. To configure Layer 3 EtherChannels, you must first create the port-channel logical interface and then put the Ethernet interfaces into the port-channel. Use the steps outlined in the following table to create 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...

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...

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 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...

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...

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...

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...

Floating Static Routes

Floating static routes are an enhancement to static routes that use administrative distance to appropriately weight the backup route in relation to routes learned through dynamic routing protocols. R4(config) ip route 172.16.10.0 255.255.255.0 bri0 0 200 R4(config) ip route 172.16.16.0 255.255.255.0 bri0 0 200 Floating static routes are static routes with an administrative distance (AD) greater than dynamically learned routes 2001, Cisco Systems, Inc. All rights reserved. Cisco CCIE Prep v1.0...

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...

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...

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...

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)...

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.

Full Mesh Requirements

* Route reflection can be used to get around the full mesh j iBGP requirement 2002, Cisco Systems, Inc. All lights reserved. Once a BGP session has been established, updates are exchanged to provide all the locally known routes with only the best path advertised. Incremental update messages are exchanged later. If the best path is received from an eBGP peer, then it is advertised to all peers. This is another very important concept to understand. If a BGP speaker receives an update from an eBGP...

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...

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...

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...

EIGRP Split Horizon

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...

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,...

Distribute Lists

Distribute lists allow granular advertisement control router config-router) neighbor ip-address peer-group-name distribute-list access-list in out Rl(config) access-list 1 deny 172.16.0.0 0.0.254.255 Rl(config) access-list 1 permit any Rl(config) access-list 1 deny 172.16.0.0 0.0.254.255 Rl(config) access-list 1 permit any Rl(config-router) neighbor 172.16.134.3 distribute-list 1 out 2002, Cisco Systems, Inc. All lights reserved. One method to filter BGP advertisements is to use distribute...

Debugging ATM

All rights reservec arp Show ATM ARP events. Displays messages pertaining to the process of mapping an ATM Network Service Access Point (NSAP) address to an IP address. Here is a sample output for this command ATM ARP events debugging is on R7 ping 10.1. 20 32 54 ATMARP(ATM1 0.2) Learned address through INARP reply for CCIE R7 ping 10.1.1 20 32 57 ATMARP(ATM1 0.2) Learned address through INARP reply for CCIE Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2...

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...

Dialer Profiles

Dialer Profiles allow a great deal of flexibility in the configuration of DDR circuits, allowing one physical interface to be used for multiple functions. 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...

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...