MPLS: OSPF sham-links

Introduction The provider's MPLS cloud has three routers namely - R1 (P-router), R2 (PE-R2) and R3 (PE-R3). These routers formed OSPF adjacency with one another. R2 and R3 are iBGP neighbors peering with each other's loopback address. The TTL propagation within the MPLS cloud was suppressed with no mpls ip propagate-ttl command. This is to … Continue reading MPLS: OSPF sham-links →

BGP: Injecting IGP route into BGP without redistribution

The diagram is complicated with an additional link, and instead of full BGP route in AS65000, the BGP route is propagated with the help of OSPF. In previous lab, the BGP full mesh was established by peering both subnets of a BGP router. However this step can be simplified by peering the BGP speaker's loopback … Continue reading BGP: Injecting IGP route into BGP without redistribution →

MPLS VPN: VRF

MPLS VPN building blocks 1. Virtual routing and forwarding (VRF) - This creates logical routing instance, each virtual instance is separated such that virtual instances to instances are not reachable. 2. MP-BGP - BGP is extended to distribute MPLS VPN tags. 3. IGP - OSPF or IS-IS among the MPLS LSRs. 4. MPLS - Using … Continue reading MPLS VPN: VRF →

MPLS traceroute and MPLS propagation TTL

All serial links among the m1,m2 and m3 routers have the same bandwidth, I need mpls trace to test if the mpls is operational as configured. Suppose I want to use loopback reachability to test, I am using m1 loopback and traceroute to m3 loopback. Notice there is no label. This is because the out … Continue reading MPLS traceroute and MPLS propagation TTL →

MPLS label distribution modes

I have realized the information in MPLS foundamentals is really really good, especially chapter 2, I have read it several times each time I read it cleared previously misinterpreted concepts. The modes are broken down into three sections: 1. Label distribution mode - The method regarding mpls label distribution. 2. Label retention mode - The … Continue reading MPLS label distribution modes →

Multi Protocol Label Switching basics

MPLS label 1. 32-bit long. 2. First 20 bits for label, second 3 bits for EXP which is used for quality of service, third 1 bit for bottom of the stack, last 8 bits for time to live. 3. Here is the break down: a. bit 0 to bit 19: Label. b. bit 20 to … Continue reading Multi Protocol Label Switching basics →

Cisco IOS Easy VPN server (Remote access vpn)

Acknowledgement I would like to thank Mr. Richard Deal in this post. Mr. Deal is able to describe complex cisco security technology into easy to understand and easy to digest manner. I have not met Mr. Deal in person nor does he know who I am, but through his books I have learned a great … Continue reading Cisco IOS Easy VPN server (Remote access vpn) →

Web Cache Communication Protocol (WCCP)

Purpose To offset the load of edge router in http request. A http request sent by a host is redirected to local content cache engine (aka content engine), content engine will then send the content back to the requesting host. Operation Other things about WCCP 1. Only works with IPv4. 2. Has two versions. 3. … Continue reading Web Cache Communication Protocol (WCCP) →

An introduction to Point-to-Point Protocol

The big picture PPP is a layer 2 WAN technology that is designed to establish connection between two nodes over a variety of network mediums. Features 1. It has built-in error detection. 2. Monitoring the quality of the link before sending frames. 3. Capability to encapsulate frames and carry them over various layer2 WAN technologies … Continue reading An introduction to Point-to-Point Protocol →

Frame relay: Multilink point to point frame relay

Reference: http://www.cisco.com/en/US/docs/ios/12_2s/feature/guide/fs_mfr.html Multilink Frame Relay (FRF.16.1) 1. This technology aggregates multiple number of physical serial interfaces into one bundle. a. This provides link redundancy i.e. if a physical link of a bundle has failed, the frame relay link will still be available. b. This also provides bandwidth aggregation from multiple serial interfaces. (See http://www.cisco.com/en/US/docs/ios/12_2s/feature/guide/fs_mfr.html#wp1054102) 2. The aggregated … Continue reading Frame relay: Multilink point to point frame relay →