Cisco IOS Resilient Configuration

The Cisco IOS Resilient Configuration feature allows for faster recovery in situations in which an attacker has compromised a router and erased its Cisco IOS image configuration file. This feature is available only on platforms with PCMCIA ATA Flash drives. When enabled, this feature saves nonerasable copies of the running Cisco IOS image and running configuration to the Flash drive. If the configuration Cisco IOS image is then erased, the secure backup copy of the Cisco IOS image can be booted...

Configuring Wireless LAN Devices

Autonomous APs must be configured individually, while the WLC provides configuration to lightweight APs. WLAN clients must also be configured this process varies depending on the client software used. Configuring Autonomous Access Points Autonomous APs can be configured in one of three ways IOS Command Line Either via Telnet or the console port. Web browser This is the Cisco preferred way. CiscoWorks WLSE For centralized configuration control. The AP must already have an IP address to use any...

Quick Reference

Denise Donohue, CCIE No. 9566 Brent Stewart Jerold Swan, CCIE No. 17783 800 East 96th Street Indianapolis, Indiana 46240 USA Denise Donohue, Brent Stewart, Jerold Swan Copyright 2008 Cisco Systems, Inc. Published by Cisco Press 800 East 96th Street Indianapolis, IN 46240 USA All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system,...

P

Nonbroadcast) networks, OSPF, 35 P2MP (Point-to-Multipoint) networks, OSPF, 34 P2P (Point-to-Point) networks IS-IS, 45 OSPF, 35 packet filtering, 236-237 packet forwarding, MPLS, 195 packet loss (QoS) causes of, 266 VoIP, 257 Packet mode (AAA), 233 packet switching, MPLS, 191 packetization (VoIP), 257 CODEC, 256 data link headers, 258 E& M connections, 255 FXO connections, 255 FXS connections, 254 ISDN phone ports, 255 Nyquist theorem, 256 PAM, 256 PSTN, 256 quantization, 256 RTP, 258-259 T1...

C

Cable Internet connections (broadband) antenna sites, 177 CMTS routers, 178-179 components of, 178 distribution networks, 177 DOCSIS cable standard, 178 FDM, 177 headend sites, 177 HFC networks, 177 modem provisioning, 179 NTSC cable standard, 178 PAL cable standard, 178 SECAM cable standard, 178 SOHO teleworker connectivity, 177-179 subscriber drops, 177 transportation networks, 177 cable modems, broadband cable Internet connections, 179 CAC (Call Admission Control), 262 call control...

About the Authors

Denise Donohue, CCIE No. 9566, is manager of Solutions Engineering for ePlus Technology in Maryland. She is responsible for designing and implementing data and VoIP networks, supporting companies based in the National Capital region. Prior to this role, she was a systems engineer for the data consulting arm of SBC AT& T. Denise was a Cisco instructor and course director for Global Knowledge and did network consulting for many years. Brent Stewart, CCNP, CCDP, CCSI, MCSE, is a network...

J K L

See also delays k values (default), EIGRP metric, 17 Keepalive messages, BGP, 60 keepalives (routers), EIGRP, 16 L1 (Level 1) routers, IS-IS, 43-44 L1-2 (Level 1-2) routers, IS-IS, 43-45 L2 (Level 2) routers, IS-IS, 43-44 labels, MPLS distributing in, 193 tables, 194 LACP (Link Aggregation Control Protocol), 124 LAN (local-area networks) QoS, 203, 272 VLAN, 9, 96, 248 Access ports, 101 best practices for, 101 capacity requirements, 101 configuration...

Basic OSPF Configuration

OSPF is configured by entering router configuration mode and identifying the range of interface addresses on which it should run and the areas they C are in. When setting up OSPF, a process ID must be used (8 is used in the O example), but the process ID does not have to agree on different OSPF - devices for them to exchange information. The network statement uses a S wildcard mask and can specify any range from a single address to all I addresses. Unlike EIGRP, the wildcard mask is not...

Hot Standby Router Protocol HSRP

HSRP is a Cisco proprietary protocol. With HSRP, two or more devices support a virtual router with a fictitious MAC address and unique IP address. Hosts use this IP address as their default gateway, and the MAC address for the Layer 2 header. The virtual router's MAC address is 0000.0c07.ACxx, where xx is the HSRP group. Multiple groups (virtual routers) are allowed. The Active router forwards traffic. The Standby is backup. The standby monitors periodic hellos (multicast to 224.0.0.2, UDP port...

OSPF Network Types

The SPF algorithm builds a directed graph paths made up of a series of points connected by direct links. One of the consequences of this directed-graph approach is that the algorithm has no way to handle a multiaccess network, such as an Ethernet VLAN. The solution used by OSPF is to elect one router, called the Designated Router (DR), to represent the entire segment. Point-to-point links fit the SPF model perfectly and don't need any special modeling method. On a point-to-point link, no DR is...

Configuring a Crypto

A crypto map pulls together the transform sets and crypto ACLs and associates them with a remote peer. A sequence number can be used when configuring a crypto map. Multiple crypto maps with the same name but different sequence numbers form a crypto map set. Traffic is evaluated against each crypto map depending on its sequence number to see whether it should be protected. This permits more complex and granular traffic filtering. The following example shows a crypto map that links the transform...

Applying the Crypto Map to an Interface

After the crypto map has been configured, it must be applied to an interface for it to take effect. It is applied at the outgoing interface the one that VPN traffic will use to reach the other end of the VPN. You might need to use a static route or otherwise adjust your routing to force traffic bound for the VPN destination networks to use the correct outgoing interface. The following example shows the crypto map TO_SERVERS applied to c interface serial 0 0 0. Note that the router replies with...

Adsl

ADSL is a popular residential service because it can carry both voice and data over one twisted pair of wires. This capability is accomplished by using either a splitter or a filter. A splitter takes the incoming analog signals and splits off the frequencies under 4 MHz to a voice line. It sends all other traffic to the DSL line. Splitters are more typically used at the CO than the subscriber premises because they require a technician to install them. A filter, or microfilter, requires no...

Troubleshooting ADSL

When troubleshooting ADSL problems, start with checking Layer 1 physical connectivity. If that checks out okay, progress to checking Layer 2 connectivity. Finally, check Layer 3. Try the following procedures when troubleshooting DSL physical layer problems 1. Check for the carrier detect light on the router's ATM interface. If it is off, use the show interfaces atm interface_number command to check the interface status. If the interface status is down, try swapping out the RJ-11 cable...

Configuring PPPoE CPE

The following tasks must be completed to configure a CPE router with for PPPoE 1. Configure the internal and external interfaces. 2. Configure a dialer interface. 4. Configure the router to act as a DHCP server. First, configure the internal Ethernet interface with an IP address. It will be the default gateway for the users. Also, configure it as the inside interface for NAT. Do not put an IP address on the external Ethernet interface. Enable PPPoE on it, and assign it to a PPPoE client dialer...

Classifying and Marking in a VoIP Network

Figure 4-2 shows what happens to the CoS and DSCP settings of a data packet as it moves through a QoS-enabled LAN. Figure 4-2 CoS and DSCP Changes for a Data Packet Data DSCP 56 CoS 7 IP Header 802.1p bits PC with 802.1Q-capable NIC sends a packet through the phone. PC user sets the packet's DSCP to 56 (IP precedence 7) and CoS to 7. traffic to 0 before forwarding to Access switch. Does not change the DSCP value. Switch is configured classify and mark data traffic. It sets both DSCP and CoS on...

Wireless LAN Overview

Devices on a wireless LAN (WLAN) transmit and receive data using radio or infrared signals, sent through an access point (AP). WLANs function similarly to Ethernet LANs with the access point providing connectivity to the rest of the network as would a hub or switch. WLANs use an Institute of Electrical and Electronics Engineers (IEEE) standard that defines the physical and data link specifications, including the use of Media Access Control (MAC) addresses. The same protocols (such as IP) and...