Questions tagged [mpls]

For questions about Multi-Protocol Label Switching (MPLS), the layer 2.5 protocol used as a transport layer for Traffic Engineering, some Layer 2 & 3 VPN's, and VPLS.

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Issue in Xconnect VPLS [closed]

hello all im having issue in configuring VPLS, can you please guide me as i'm having issue configuring xconnect(its saying encapsulation is not supported in this circuit), which ver of cisco router ...
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How is the destination MAC address filled during MPLS label switching?

During IP packet forwarding, after a LPM(ip lookup) done on the FIB, it will fetch the Nexthop ip address and the egress interface to send out the packet. Now, ARP table lookup is done for this ...
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How do I set up IPv6 multicast over an MPLS carrier?

I'm setting up an MPLS carrier with VPNs in GNS3, using Cisco 7200 routers. Exact version I'm using is C7200-ADVIPSERVICESK9-M Version 15.2(4)S5, but I'm willing to upgrade/change if that's needed. On ...
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exchange routes and prefixes of remote clients in the mpls

is it possible to exchange routes and prefixes of remote clients in the mpls by an ospf? to avoid creating each time BGP sessions between PEs especially when the topology is scalable
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What is the difference between MPLS, MPLS VPN and IPsec VPN tunnel?

What is the difference between MPLS, MPLS VPN and IPsec VPN tunnel? I know that MPLS is a type of WAN. and IPsec VPN tunnel is an encrypted connection (private) over the internet. But what is MPLS VPN?...
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No Adjacency-SID label in packets in SR topology

I configured Segment-Routing on Cisco IOS XE 17.03.3 in lab environment. You can see topology in the attachment. I configured IS-IS as IGP protocol. It also advertise SR labels. Global-SID static ...
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Do Juniper l2circuit services (ccc) support a mismatched encapsulation type?

I am building an l2circuit ccc (draft-martini) between an EX4500 and an MX204. The issue is that I need to have mismatched l2circuit encapsulation-type on either side. The East-coast EX4550-32F (Junos:...
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What's the advantage of using SDWAN over MPLS/Circuit Lines?

I am trying to figure out. What's the advantage of using SDWAN over MPLS/Circuit Lines? Some Companies goal is to reduce costs so they migrate MPLS/Circuit Lines to SDWAN. Is there any engineering ...
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What are LDP-MPLS advantages?

An LDP-MPLS is deployed on a network and labels are used for packet forwarding. As you may know, LDP needs IGP and there is IGP too. Because there is no RSVP, there is no traffic engineering and there ...
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Why do we need a Route Distinguisher in VPNv4 routes if there is already a VPN label?

I know the explanation about the usage of RD, that it makes routes from different VRFs globally unique. AFAIK, a VPN route is composed of [RD] + [VPN label] + [Prefix] Isn't the VPN label, that is ...
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MPLS LDP transport address should it be always loopback IP

Can the transport address for the LDP be different from the loopback IP? LSR ID would be loopback while the transport address would be interface IP. For example, if the interface IP is the transport ...
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How to isolate in VRF clients with public IPs in MPLS ISP network

I have OSPF and MPLS enabled in network and run xconnects to transmit L2 traffic. But also have just Internet clients that want public IP addresses. So I configure public IP on interface towards ...
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What are the benefits of using a transport label in L3VPN?

If not utilizing any form of TE (Traffic Engineering), are there any benefits of using a transport label in L3VPN - instead of just using a simple IPinIP tunnel? e.g. if traffic is egressing PE1 with ...
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How are MPLS routers connected to each other?

So MPLS is one of the many ways to connect two or more distant sites. In other words, it is some kind of a "WAN solution". But what is the "WAN solution" for MPLS? Take for example ...
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Is this how ATM and SONET work?

This is how I visualize how SONET carry ATM, and how ATM carry IP: Is my visualization correct?
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How does a Cisco router determine if a packet is IP routed or label switched?

How does a Cisco Router (IOS-XE) decide if a Packet will be MPLS Label switched or ip routed? In a Juniper MX MPLS Pathes have an own Administrative Distance (or Preference in Junipers wordings) So ...
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Getting VRF to work (and some other questions)

I'm messing with BGP/MPLS for the first time and I have some doubts both in if I'm doing something wrong with my configuration and if it is the best approach, hope you guys can clarify me a bit here. ...
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Many ways of configuring MPLS pseudowires, and choosing only one

I am discovering MPLS configuration on Cisco ASR920, and for almost any "thing" that can be configured, there is often two or more ways to do it. For example, given this configuration: ...
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MPLS-BGP - VPN isolation - RFC 4364

In Section 6 of RFC-4364, it is stated that, if MPLS is being used as the tunneling technology (in the scope of forwarding VPN-IPV4 traffic from one PE to an other) , this means that a router in the ...
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Transporting an Ethernet Port in a LDP Based VPLS Instance on Juniper MX routers

We are currently transporting an Ethernet Port using LDP Based Layer 2 VPN service (P2P PW) in Juniper MX.This P2P LDP PW is up and currently working. Below is the configuration against this:- set ...
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3 votes
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MPLS xconnect L2VPN with tagged interface (subinterface) and untagged interface

We need to extend a specific device directly connected to the core network to an existing L2VPN with an MPLS xconnect L2VPN. But we encounter a problem. Indeed, one side recquire sub interface and ...
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How to connect EVPN DC Fabric to MPLS IP VPN Backbone

Let's suppose that we have a common Clos EVPN/VXLAN-based DC fabric with IP gateways on leaves (anycast gateways). Also there is a lot of different IP VRFs inside a fabric where end hosts reside. What ...
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Interconnecting sites with different networks and VLANs

I've got three sites, let's call them Production Plant, Remote 1 and Remote 2. They're not big networks. The Production Plant has two internal networks that has control systems designed for all being ...
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What is the difference between Targeted LDP and Directed LDP in MPLS?

Please explain the main differences (use cases) between Targeted LDP and Directed LDP in MPLS ?
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Do X.25/Frame Relay/ATM/MPLS have their own switches?

In the context of networking when we say "switch" we always think of Ethernet switch. But do we have X.25 switch, Frame Relay switch, ATM switch, and MPLS switch? If yes, how are they ...
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How are labels in LDP "Label Mapping Message" associated with IP prefix?

Let's say, that I have two directly connected routers r1 and r2. For example, I do see that the r2 sends a Label Mapping Message to r1 and provides several labels including 21(0x15): r1 associates ...
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Why does Junos create two entries in LIB for single tag- one with "S=0" and other with implicit "S=1"?

In the penultimate LSR there are following two entries for label 301040: root@r2> show route table mpls.0 protocol rsvp mpls.0: 14 destinations, 14 routes (14 active, 0 holddown, 0 hidden) + = ...
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Why are the LDP installed LSPs not seen in the output of "show mpls lsp" in Junos?

I have established a LDP session between routers r1(lo0.0 has 192.168.1.1 configured) and r4(lo0.0 has 192.168.1.4 configured). According to show route table inet.3 192.168.1.4 in r1 the BGP prefixes ...
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What's the difference between L2TP and L2TPv3? [closed]

Is L2TPv3 an improvement of L2TP or a completely different technology? Other than "it scales better" and "the non-proprietary MPLS" I can't find much information about it that's ...
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How to compare two DSCP ? which one of DSCP 28 and 34 (decimal) has more priority?

How to compare two DSCP ? for example which one of DSCP 28 and 34 (decimal) has more priority ?
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2 votes
1 answer
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Brocade L2VPN Route Reflector

I am trying to create an MPLS VPLS network where the VPLS instances are auto-discovered via BGP L2VPN. The issue I'm currently facing is that the routes are not reflected and there seems to be no ...
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1 vote
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Secure MPLS configuration: Does TCP port 646 (LDP) need to be generally exposed?

I am looking for expertise on MPLS configurations and security. A recent Nmap scan of my organization's public IPv4 perimeter networks has discovered a system which appears to be listening on TCP port ...
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1 vote
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Why is SD-WAN a more suitable option than MPLS for cloud? [closed]

I keep coming across the statement that because of the growth in cloud computing, SD-WAN is a more suitable option than MPLS for connecting remote sites. Can anyone give me an explanation why?
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Pros and cons of using VPLS instead of using MPLS alone

What are the pros and cons of using VPLS instead of MPLS alone? What are the typical cases where VPLS is used?
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3 votes
2 answers
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MPLS : who owns the ingress & egress routers?

I'm trying to understand MPLS. It states that the routing doesn't happen at each router, and it starts with a "Label Edge Router". For example, if company X uses ATT as the provider for MPLS, then ...
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How MPLS solve the fragmentation problem?

MPLS appends a label for any packet enters its network. If a packet is equal to the maximum packet size, then packet may get fragmented after appending the label. How does MPLS solve this problem?
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Bandwidth limit between CPE and Provider Equipment

I have 4 different WAN links for redundancy one of them is 15mbps MPLS and the other ones are 30mbps Internet , 50 mbps Internet and 10 mbps MPLS , the way that it is set up is that we have load ...
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5 votes
1 answer
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juniper vlan-ccc vs ethernet-ccc for eompls

In juniper ethernet-ccc transports customer's vlan end to end. Does vlan-ccc also transport customer's vlan across as well?
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MPLS route-target export

"Route-target export" is used to export routes form VRF to mBGP - i need to know the rules which tells which routes will be exported. For example : if VRF-RED have 10 Routes which include static ...
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1 vote
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Is it mandatory to upgrade backup ILL connection when MPLS circuit is upgraded?

In our office we have both MPLS and ILL connection. We recently upgraded our office MPLS bandwidth connection from 20 Mbps to 50 Mbps. Currently 20 Mbps ILL connection we have. Is it mandatory to ...
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Does CSR1000v on AWS support IPv6?

I'm trying to implement Segment Routing IPv6 (SRv6) in Cisco CSR1000v on AWS. I'm having issues with IPv6 which gave the impression that IPv6 data plane does not work. Similarly, I configured a ...
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1 vote
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LDP: which FEC an egress router has to advertise when using Ordered Control?

If an egress router knows how to reach a set of distinct and indipendent networks (say, two or more non overlapping IP prefixes in its routing table), is it expected to announce one single FEC for ...
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LDP: which FEC to advertise when using Ordered Control?

I have the following doubt: if an egress router knows how to reach a set of subnets, is it expected to bind all those remote destinations in just a FEC (one label) or has it to bind a label for each ...
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Next protocol in MPLS header

How come MPLS header has no next protocol ID field? How can a parser tell for sure which protocol is next? BOS field only indicates that the next header is not MPLS, which is not enough to ...
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2 votes
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Should the Loopback address be unique across the network?

I have an MPLS network where every site has two PEs for redundancy. and I want to configure a set of loopback interfaces on every PE router for routing traffic between different VRFs. is it possible ...
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3 votes
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MPLS labels between CE and PE

What use cases are there for MPLS labels to be exchanged between CEs and PEs? I'm seeing Carrier Supporting Carrier (Carriers' Carrier) as a potential use case, but are there others? EDIT: I have ...
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Creating an overlay network using ASA and VXLAN over IP MPLS

I need to extend an existing VLAN from a branch LAN to DC. As a matter of fact I noticed that Cisco ASA 5500X have VXLAN capabilities. I am relatively new to VXLAN and I need some help to find the ...
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Usable IP addresses and MPLS

I work at a company where I am partly responsible for IT, just because I'm semi technical and we're not big enough to warrant a dedicated role for someone else. I was asked to look into upgrading out ...
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5 votes
3 answers
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Traceroute doesn't show one hop?

I have an interesting issue where my traceroute skips one hop on the way. I do not know why but it seems to be some kind of Juniper behaviour which I do not understand yet. Blue routers are Cisco ...
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4 votes
1 answer
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Extending a subnet across a WAN link vs routing

probably a noob question but any help is appreciated. Question: What are the disadvantages of spanning L2 subnets across a WAN as opposed to a routed connection? Background: I've got a client who's ...
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