By 1985, the ARPANET was heavily utilized and burdened with congestion. In response, the National Science Foundation initiated phase 1 development of the NSFNET. The NSFNET was composed of multiple regional networks and peer networks (such as the NASA Science Network) connected to a major backbone that constituted the core of the overall NSFNET. In its earliest form, in 1986, the NSFNET created a more distributed, three-tiered network architecture. This architecture connected..
IS-IS is limited because its metric has only six bits. This means that the value of an individual metric can range only from 0 to 63. The total length of a path between two ISs can be 1023 maximum. You should consider the metric in advance. The default value is assigned to be 10, independent of the bandwidth for all types of links and for both level 1 and level 2. The interface metric can be modified for each level independently. Configuration for level 1 metric is as follows..
Hierarchical Queuing Architecture for Frame Relay
When Frame Relay encapsulation is configured for serial interfaces on Cisco routers, two levels of queuing can exist for the serial interfaces. By default, when the Frame Relay interface is congested, the interface-level queue is used to store the excess packets at the interface level until the interface becomes free to send them. In addition, a second level of queuing at the Frame Relay PVC level is possible with Frame Relay Traffic Shaping. NOTE WFQ is the default queuing..
EIGRP Default AD Defeats Loop from EIGRP to OSPF to EIGRP
The default AD settings for EIGRP takes care of the domain loop problem when redistributing between EIGRP and OSPF. First, consider an EIGRP and OSPF domain with two redistribution points (Routers RD1 and RD2), as shown in Figure 10-4. The figure shows a general idea of route advertisements for subnet X, which exists in the EIGRP domain. (Note: to reduce clutter, the figure shows only route advertisements that affect router RD2’s logic; the same issue exists on both redist..
Configuring Multiple DHCP Servers per Subnet
You can configure multiple routers to act as DHCP servers for a single subnet, by ensuring that they don't use the same pool of addresses. Here's Router1: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#ip dhcp pool 172.22.1.0/24 Router1(dhcp-config)#network 172.22.1.0 255.255.255.0 Router1(dhcp-config)#default-router 172.22.1.1 Router1(dhcp-config)#domain-name oreilly.com Router1(dhcp-config)#dns-server ..
