CCIE R&S – InternetworkPro

November 25, 2014

1.1.c Network Theory – Explain General Network Challenges

In this post, I’ll provide an explanation of the following challenges networks may encounter: 1.1.c Explain general network challenges 1.1.c (i) Unicast flooding 1.1.c (ii) Out of order packets 1.1.c (iii) Asymmetric routing 1.1.c (iv) Impact of micro burst Unicast flooding itself is a needed and normal switching process when an incoming unicast dataframe inbound on a particular VLAN with a destination IP does not have its destination mac-address in the CAM table, the unicast dataframe is broadcast out all […]

November 21, 2014

1.1.b Network Theory – Cisco Express Forwarding

The following key concepts will be explained here: 1.1.b Identify Cisco express forwarding concepts 1.1.b (i) RIB, FIB, LFIB, Adjacency table 1.1.b (ii) Load balancing Hash 1.1.b (iii) Polarization concept and avoidance Cisco Express Forwarding (CEF) is a cisco proprietary technology which allows for more efficient and faster layer 3 switching. It is a type of interrupt context switching as opposed to process switching. It offloads much of the processing involved in layer 3 switching to the hardware; unlike the […]

November 19, 2014

1.1.a Network Theory – IOS vs IOS XE

IOS is the acronym for Cisco’s Internetworking Operation System, it is the brain (software OS) behind the brawn (Cisco hardware) for the complex tasks of internetworking; managing and controlling the diverse networking hardware resources and functions; modern IOS consists of multiple modular subsystems. IOSXE improves on IOS by improving portability across platforms and adding extensibility by being built on POSIX (standards for software compatibility with OSes including variants of UNIX)). From the CCIE R&S v5 written blueprint, we’ve the following questions which requires […]

November 19, 2014

CCIE R&S v5 Written Blueprint

The following is a list of the topics covered in the CCIE R&S v5 written blueprint as published by Cisco; it is to be used as a general guideline. I’m planning to publish posts of the topics in the order listed by Cisco for the CCIE R&S v5 written blueprint; in preparation for taking the written exam. 10% 1.0 Network Principles 1.1 Network theory 1.1.a Describe basic software architecture differences between IOS and IOS XE 1.1.a (i) Control […]

April 13, 2014

BGP Key Concepts Part I

Border Gateway Protocol (BGP) is an Exterior Gateway Protocol (EGP) used for routing and reachability between inter-autonomous systems. Autonomous system can be defined as an administrative unit with common policies for routing. IGPs are used for routing and reachability within an autonomous system (as earlier defined; note different from concept of Areas in OSPF); typically within a customer network. BGP is used on the internet and between ISPS. BGP comes in two forms IBGP and EBGP. Internal BGP (IBGP) is […]

August 17, 2012

OSPF Key Concepts Part II/II

For configuring basic OSPF: Router(config)#router ospf<Process ID> Router(config)#router ospf 2 Router(config-router)#network <Subnet ID/Network ID> <Wildcard Mask> Area<#> Router(config-router)#network 192.168.10.4 0.0.0.3 Area 0 Router(config-router)#network 130.50.10.64 0.0.0.31 Area 0 Router(config)#interface loopback0 Router(config-if)#ip ospf network point-to-point (P2P, instead of w.x.y.z/32 you will see w.x.y.z/proper mask) Useful show commands for OSPF: Router#show ip ospf neighbor Router#show ip ospf interface Router#show ip route ospf For configuring OSPF to broadcast itself as the default-gateway: Router(config)#ip route 0.0.0.0 0.0.0.0 serial 0/0 Router(config)#router ospf <Process ID> […]