Free tools Windows power users keep installed
One-click scans. No signup required.
A label switching router (LSR) is a router that takes part in MPLS (Multiprotocol Label Switching). It forwards packets by looking at a short label instead of doing a full network-layer lookup at every hop. The IETF’s MPLS architecture standard, RFC 3031 (January 2001), defines it as “an MPLS node which is capable of forwarding native L3 packets.” Cisco’s documentation uses the same term, sometimes written “Label Switch Router.”
How an LSR forwards a labeled packet
RFC 3031 describes the procedure. When a labeled packet arrives, the LSR examines the top label in the label stack. It uses the Incoming Label Map (ILM) to map that label to a Next Hop Label Forwarding Entry (NHLFE). The entry gives the next hop and says how to handle the packet. The LSR then applies the indicated operation to the label stack and forwards the packet.
As an Amazon Associate I earn from qualifying purchases.
Cisco’s terminology calls the forwarding table the Label Forwarding Information Base (LFIB). It determines the hop-by-hop path.
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Clear out junk files and repair common Windows errors3Fix the driver behind crashes, sound loss and screen glitchesWhat a label means
A label identifies a forwarding equivalence class (FEC). A FEC is a group of packets that the network forwards the same way. Two points from RFC 3031 are easy to get wrong:
#1 Best Overall
- RB/750 - The hEX lite is a small five port Ethernet router enclosed in a durable plastic case
- The RB750r2 (hEX lite) is a small five port ethernet router in a nice plastic case.
- There simply is no choice when it comes to managing your wired home network, the RB750r2 (hEX lite) has it all.
- Not only it's affordable, small, good looking and easy to use - It's probably the most affordable MPLS capable router on the market
- No more compromise between price and features - RB750r2 has both. With its compact design and clean looks, it will fit perfectly into any SOHO environment.
- A label is not an encoding of the destination address. It stands for the class of traffic.
- Labels are locally significant. The label value can differ between adjacent hops, so the packet’s label changes as it crosses the network. Cisco’s overview illustrates this.
Cisco’s beginner FAQ (updated February 17, 2025) describes the MPLS label as four bytes. These are protocol-format widths, not performance figures:
| Field | Size |
|---|---|
| Label value | 20 bits |
| Traffic class | 3 bits |
| Bottom-of-stack flag | 1 bit |
| TTL | 8 bits |
Ingress, transit and egress roles
These terms describe where a router sits on a particular packet’s path and what it does to the label stack. They are not separate hardware categories.
Rank #2
| Role | What it does |
|---|---|
| Ingress (label edge router, LER) | Inspects the incoming packet, maps it to a FEC and pushes the label stack. |
| Transit LSR | Looks at the top label, commonly swaps it, and forwards the packet to the next hop. |
| Egress (LER) | Pops the label and forwards the underlying packet onward. |
Cisco’s example follows this sequence: the ingress router imposes a label, transit routers swap it, and the egress router removes it.
Not every LSR is transit-only. The RFC definition is based on capability, and Cisco identifies provider edge (PE) routers as ingress and/or egress LERs. “Transit LSR” describes a router’s role on one path, not a permanent type.
Rank #3
- hEX lite is a small five port ethernet router in a nice plastic case
- Not only this is an attractive looking tiny SOHO unit, its price is lower than the RouterOS license alone
- It’s probably the most affordable MPLS capable router on the market! No more compromise between price and features - hEX lite has both
- With its compact design and clean looks, it will fit perfectly into any SOHO environment
- 113 x 89 x 28mm dimensions, 850 MHz CPU nominal frequency, 64 MB RAM, RouterOS L4
Related terms
- MPLS: the architecture in which labels drive packet-forwarding decisions.
- FEC: a set of packets given equivalent forwarding treatment.
- LSP (label switched path): the path through one or more LSRs taken by packets in a FEC. Cisco’s overview gives LDP and BGP as examples of how label information is signaled.
- LER / PE: an edge router that applies labels at ingress and/or removes them at egress.
- LFIB: Cisco’s name for the label forwarding table.
This article covers the generic MPLS term. Commands and behavior vary by vendor and platform.
Quick Recap
Rank #4
- 【AC1200 Dual-band Wireless Router】Simultaneous dual-band with wireless speed up to 300 Mbps (2.4GHz) + 867 Mbps (5GHz). 2.4GHz band can handles some simple tasks like emails or web browsing while bandwidth intensive tasks such as gaming or 4K video streaming can be handled by the 5GHz band.*Speed tests are conducted on a local network. Real-world speeds may differ depending on your network configuration.*
- 【Easy Setup】Please refer to the User Manual and the Unboxing & Setup video guide on Amazon for detailed setup instructions and methods for connecting to the Internet.
- 【Pocket-friendly】Lightweight design(145g) which designed for your next trip or adventure. Alongside its portable, compact design makes it easy to take with you on the go.
- 【Full Gigabit Ports】Gigabit Wireless Internet Router with 2 Gigabit LAN ports and 1 Gigabit WAN ports, ideal for lots of internet plan and allow you to connect your wired devices directly.
- 【Keep your Internet Safe】IPv6 supported. OpenVPN & WireGuard pre-installed, compatible with 30+ VPN service providers. Cloudflare encryption supported to protect the privacy.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
