Advanced cisco router configuration

Advanced Cisco Router Configuration Exam Study Guide

1. Describe the key requirements of scalable internetwork?
2. Select a Cisco IOS feature as a solution for a given internetwork requirement.

Reliable and available:
• Reachability – Scalable routing protocols such as OSPF, EIGRP, and NLSP use metrics that expand the reachability potential for routing updates because they usecost, rather than hop count, as a metric.
• Fast convergence time – Scalable protocols can converge quickly because of the router’s ability to detect failure rapidly and because it only sends changes not the entire routing table.
• Alternate Paths – Scalable protocols, such as EIGRP and OSPF keep record of alternate routes in case the preferred route is not available.
• Loadbalancing – Because scalable protocols maintain entire network topology, they are able to transport data across multiple paths to a given location simultaneously.
• Tunnels – ability to transport various protocols within IP
• Dial backup – Use the backup link when the primary fails or when the primary is congested.

Responsive:
• Weighted fair queuing – An automated methodthat provides fair bandwidth allocation to all network traffic. It ensures that high-bandwidth conversations do not consume all bandwidth.
• Priority queuing – A particular traffic type is prioritized higher than all other traffic types.
• Custom queuing – Each traffic type gets a minimum of the share bandwidth at all times.

Efficient:
• Access lists – Can be used topermit or drop protocol update traffic, data traffic, and broadcast traffic.
• Snapshot routing – Allows peer routers to exchange full distance vector routing information upon initial connection, then on a predefined interval.
• Compression over WANs – Cisco supports TCP/IP header compression and data (payload) compression.
• Dial-on-deemed routing – Active links are created onlyafter interesting traffic is detected by the router.
• Switched access – Packet-switched networks (X.25 or Frame Relay)
• Route summarization – Supported by RIP 2, EIGRP, OSFP
• Incremental updates – Sends only the topology changes when the changes occur rather than the entire routing table contents at fixed intervals.

Adaptable:
• Network must support routableand nonroutable traffic

Accessible but secure:
• Dedicated access – T1/E1
• Switched access – Frame Relay, X.25, SMDS, and ATM
• Exterior protocol support – Exterior Gateway Protocol (EGP) and Border Gateway Protocol (BGP)
• Access lists – Can be used to permit or drop protocol update traffic, data traffic, and broadcast traffic.
• Authentication protocols –WAN connections using PPP, we can use PAP or CHAP.

3. Describe causes of network congestion.
4. List solutions for controlling network congestion.

Congestion occurs when the data traffic exceeds the data-carrying capacity of the link

Traffic in an IP Network (Sources of data and overhead traffic):
• User applications
• Routing protocol updates
• Domain nameserver (DNS) requests
• Encapsulated protocol transport

Traffic in an IPX Network (Sources of data and overhead traffic):
• User services
• Routing protocol updates
• Service Advertising Protocol (SAP) announcements
• Client/Server keepalive updates

Datalink layer Traffic concerns
• Address Resolution Protocol (ARP) to resolve logical-to-physicaladdressing issues
• Keepalives to maintain connectivity
• Tokens for accessibility
• Time to Live updates

Control network congestion by:
• Filtering user and application traffic.
• Filtering broadcast traffic
• Adjusting timers on periodic announcements
• Providing static entries in tables
• Prioritizing traffic...