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 →

MPLS Layer 3 VPN

Acknowledgement Without MR.Keith Barker's 21 minutes video instruction, constructing MPLS VPN lab will take a longer time. His 21 minutes video instruction summarizes all. MR. Keith Barker has amazing skills to translate complicated concepts into simpler and easier to understand concepts. Now it is clearer to me and I believe it will be easier on … Continue reading MPLS Layer 3 VPN →

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 →

MPLS label

CCIE routing and switching exam certification guide 4th edition, page 831, chapter 19, figure 19-8 has a wrong label on PE2 LSR, the locally assigned label for 10.3.3.0/24 prefix should be 3 instead of 4. Although this figure is a concept figure aim to let readers to understand the mpls label switching concepts, it should … Continue reading MPLS label →

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 →

MPLS: Frame-mode MPLS configuration

Step 1: Enable CEF 1841-1# ip cef 1841-2# ip cef 3825-1# ip cef Step 2: Configure IGP 1841-1# router ospf 1 router-id 11.11.11.11 log-adjacency-changes passive-interface default no passive-interface FastEthernet0/0 network 192.168.0.1 0.0.0.0 area 0 3825-1# router ospf 1 router-id 22.22.22.22 log-adjacency-changes passive-interface default no passive-interface GigabitEthernet0/0 no passive-interface GigabitEthernet0/1 network 192.168.0.2 0.0.0.0 area 0 network … Continue reading MPLS: Frame-mode MPLS configuration →

MPLS: Basic configuration

1. Enable CEF (default is on) 2. Configure an IGP (ospf, eigrp, rip or IS-IS) 3. Define label distribution protocol (optional) 4. Assign LDP router-id. (Optional. Highest loopback address is the LDP router's ID, if loopback not available then highest ip address on physical interface is the router's id, this command force an interface to … Continue reading MPLS: Basic configuration →