Learning IOS and JUNOS

Beginning April 1, 2010, Cisco will allow Cisco 360 Learning Program students who attend a Cisco CCIE® Routing and Switching or CCIE Voice workshop to request a waiver and skip the  Core Knowledge Section  of the CCIE lab exam.  All waiver requests must be approved by the workshop instructor.  No end date for the Core Knowledge Waiver has been announced, but Cisco will provide at least 60 days’ notice before discontinuing the waiver. During a Cisco 360 Learning Program workshop, students complete a series of performance assessments that demonstrate their understanding of the CCIE material and serve the same purpose as the Core Knowledge section of the exam.  Therefore, Cisco 360 Learning Program students who use the waiver will not be required to type out answers to the Core Knowledge questions and will be allowed to move immediately to the next section of the lab exam. To qualify for the waiver, workshop students should contact their instructor 45 days in ad...

When you configure PortFast on an access or trunk port, you assure that switch it should not expect a switch on this path. With this assurance, the switch can pass right through forward delay and go directly to forwarding when it gains link. By default, PortFast does not disable STP on the port, but by skipping the listening and learning stats you do increase the probability of creating a loop if a switchin connected. To protect against this situation, you can enable BPDU guard or BPDU filter globally for PortFast port. BPDU guard will error-disable the port if a BPDU is recevied. Switch(config)# spanning-tree portfast bpduguard When the BPDU filter is enabled globally, it causes PortFast ports to stop sending BPDUs. If a BPDU is recevied, the PortFast feature is disabled for that port and normal STP operation resumes. Switch(config)# spanning-tree portfast bpdufilter

Introduction The Context-Based Access Control (CBAC) feature of the Cisco IOS® Firewall Feature Set actively inspects the activity behind a firewall. CBAC specifies what traffic needs to be let in and what traffic needs to be let out by using access lists (in the same way that Cisco IOS uses access lists). However, CBAC access lists include ip inspect statements that allow the inspection of the protocol to make sure that it is not tampered with before the protocol goes to the systems behind the firewall. Prerequisites Requirements There are no specific requirements for this document. Components Used This document is not restricted to specific software and hardware versions. Conventions For more information on document conventions, refer to the Cisco Technical Tips Conventions . Background Information CBAC can also be used with Network Address Translation (NAT), but the configuration in this document deals primarily with pure inspection. If you ...

Introduction In multicast VLAN networks, subscribers to a multicast group can exist in more than one VLAN. If the VLAN boundary restrictions in a network consist of Layer 2 switches, it might be necessary to replicate the multicast stream to the same group in different subnets, even if they are on the same physical network. Multicast VLAN Registration (MVR) routes packets received in a multicast source VLAN to one or more receive VLANs. Clients are in the receive VLANs and the multicast server is in the source VLAN. Multicast routing has to be disabled when MVR is enabled. Refer to the configuration guide at Understanding Multicast VLAN Registration for more information on MVR. This document provides a simple topology: a stack of Catalyst 3750 Switches with multicast source/receivers connected to it, a working configuration, and output of commands to verify whether the MVR works or not when a stream is sending. Prerequisites Requirements There are no s...

MRM Multicast Routing Monitor (MRM) facilitates automated fault detection in a large multicast routing infrastructure. MRM is designed to alert a network administrator of multicast routing problems near to real-time. MRM has two components: MRM tester and MRM manager. MRM tester is a sender or receiver. MRM is available in Cisco IOS Software Release 12.0(5)T and later. Only the MRM testers and managers need to be running the MRM-supported Cisco IOS version. Test Sender Configuration interface Ethernet0 ip mrm test-sender Test Receiver Configuration interface Ethernet0 ip mrm test-receiver Test Manager Configuration ip mrm manager test1 manager e0 group 239.1.1.1 senders 1 receivers 2 sender-list 1 access-list 1 permit 10.1.1.2 access-list 2 permit 10.1.4.2 Output from the show ip mrm manager command on Test Manager is shown here: Test_Manager# show ip mrm manager Manager:test1/10.1.2.2 is not running Beacon interval/hold...

Pragmatic General Multicast (PGM) is a reliable multicast transport protocol for applications that require ordered, duplicate-free, multicast data delivery from multiple sources to multiple receivers. PGM guarantees that a receiver in the group either receives all data packets from transmissions and retransmissions or can detect unrecoverable data packet loss. There are no PGM global commands. PGM is configured per interface with the ip pgm command. You must enable Multicast routing on the router with PIM on the interface.

There are two types of BPDU's: configuration BPDU's (c-BPDU) and topology change BPDU's (tcn-BPDU). Designated Bridges generate c-BPDU's. Root Ports and BLocked Ports listen for c-BPDU's. c-BPDU's originate from the root bridge and flow out towards the edge of the spanning tree, c-BPDU's are re-generated at every bridging device that receives them. tcn-BPDU's originate from root ports and flow towards the Root Bridge. c-BPDU's are the heartbeat of the Spanning Tree, tcn-BPDU's are the heart attack of the spanning tree.

Updated from Cisco 360 Workshop 1 Vol.1 1. Highest weight(default=0) 2. Highest local preference(default=100) 3. Locally originated(Next hop:0.0.0.0, weight=32768) 4. Shortest AS path length 5. Lowest origin code(IGP 6. Lowest MED(default=0) 7. EBGP over IBGP 8. If internal, prefer path with lowest IGP metric to next hop 9. If external, consider multipath (NEW!) 10. If external, prefer old one 11. Lowest router ID or originator ID 12. Minimum cluster list length (NEW!) 13. Lowest neighbor address