Category Archives: MPLS

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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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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 … Continue reading

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