Category Archives: mpls

Layer-2 and Layer-3 VPN: From JUNOS

Common terminologies: Customer-edge, provide-edge, provider router. VRF – Virtual Routing and Forwarding table: Used in L3 VPN to store customer routes. VFT – Virtual Forwarding table: Advertisements

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Junos/IOS RSVP tunnel configuration

root@Juniper> show configuration interfaces em0 { unit 0 {

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Advanced MPLS: From JUNOS

Constrained Shortest path first (CSPF) CSFP is the modified version of SPF algorithm where the data is taken from TED (Traffic engineering database) which has much information about networks like each router’s interface bandwidth, available priority values and other administrative … Continue reading

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RSVP and LDP: From JUNOS

Resource Reservation Protocol (RSVP): IP protocol number: 46 (0x2e in Hex). Each RSVP packet has common RSVP header which consist of following fields: Version – 4 bits – set to 0x01 Flags – 4 bits –000A. When bit A is … Continue reading

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Basic MPLS and configuration: From JUNOS

MPLSs’ original goal was to increase the routers’ packet processing speed. But now, due to advancement in ASIC, it is primarily used for traffic engineering. Terminologies:  LSP – Label switched path. A unidirectional logical link created by MPLS protocol. LSR … Continue reading

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Export and Import map

We can selectively import/export vpnv4 prefix to a VRF using import/export map. Below is the summary; Export Map; We can match a prefix using access-list and set the extended community RT to a specific value. The Export RTs configured on the VRF … Continue reading

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MPLS VPN Notes

MPLS VPN Terminologies; CE router- Router in Customer network (C-network) which peers with service provider edge(PE- router) in Provider network (P-network) P-routers are completely unaware of VPN. Only edge-routers(PE) are aware.

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Few MPLS timers

Below are some default timer values associated with MPLS. LDP Discovery hello interval 5 secs. Can be changed by “mpls ldp discovery hello x” LDP neighbor hold interval 15 sec. Can be changed by “mpls ldp discovery hello holdtime x” LDP session … Continue reading

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MPLS Reserved Labels

RFC 3032 mentions about reserved labels whose range is from 0-15. Label-0:” Explicit IPv4 Null Label”; Purpose of this label is same as “implicit Null Label” mentioned below.

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VPLS

VPLS – Virtual Private LAN Service (VPWS – wire) For Seamless integration of networks like HDLC, Ethernet, FR, ATM. The service provider network act as a L2 virtual switch. VSI (Virtual switching Identifier) is used for packet switching. VSI forwarding information has data about … Continue reading

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