The Route Reflector Preserves IBGP Attributes

The route reflector concept does not change IBGP behavior—the route reflector is not allowed to modify the attributes of the reflected IBGP routes. The NEXT_HOP attribute, for example, remains the same when an IBGP route is exchanged between RRs. This is necessary to avoid loops inside the AS. Figure 9-6 illustrates why the RR should not modify the attributes of the reflected IBGP routes. The NEXT_HOP attribute is used as an example. Figure 9-6 focuses on the portion of the..

Multiprotocol Label Switching Introduction

Multiprotocol Label Switching (MPLS) is an emerging technology that aims to address many of the existing issues associated with packet forwarding in today’s Internetworking environment. Members of the IETF community worked extensively to bring a set of standards to market and to evolve the ideas of several vendors and individuals in the area of label switching. The IETF document draft-ietf-mpls-framework contains the framework of this initiative and describes the primary go..

Neighbor Loss and LSP Regeneration

Refer to Figure C-2 to see what happens when Router B reboots for some unknown reason. Router A does not, as you might expect, immediately flush the LSPs that Router B has advertised. It waits until the Remaining Lifetime fields for these LSPs reach 0 (they time out), and then floods to the rest of the network that they are unreachable and flushes them from its database. Router A does not flush the LSP that is advertised by Router B for NSAP 47.0189.00C0.AF56.25B6.00 until..

Using Better Password-Encryption Techniques

Cisco introduced the enable secret password to improve the security of the enable password command. This command uses the cryptographically strong MD5 algorithm to encrypt passwords. It it extremely difficult to crack this algorithm. In fact, there are no known ways to uniquely reverse MD5 encryptions, which is why it is called a nonreversible algorithm. When you configure the router with an enable secret password, it will encrypt your enable password whether you have the se..

Defining DHCP Configuration Options

You can configure a wide variety of DHCP parameters for configuring client workstations: Router1#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router1(config)#ip dhcp pool ORAserver Router1(dhcp-config)#host 172.25.1.34 255.255.255.0 Router1(dhcp-config)#client-name bigserver Router1(dhcp-config)#default-router 172.25.1.1 172.25.1.3 Router1(dhcp-config)#domain-name oreilly.com Router1(dhcp-config)#dns-server 172.25.1.1 10.1.2.3..