Gigabit Ethernet (GigE) is the set of Ethernet standards that carry data at 1 gigabit per second (Gbps). It runs over twisted-pair copper cabling inside buildings and over fiber for longer distances. In an office it is the usual speed of desktop and switch ports; in telecom it is a common handoff speed for internet, private line and Carrier Ethernet services. When a provider says it will deliver “a gig” to your building, it usually means a Gigabit Ethernet port.
At a glance
- Gigabit Ethernet means a 1 Gbps Ethernet interface; the service running over it may be committed at a lower rate.
- Copper versions (most commonly 1000BASE-T) reach up to 100 meters over Category 5e or better cable.
- Fiber versions use pluggable optics; reach ranges from a few hundred meters to tens of kilometers depending on the optic and fiber type.
- It is the default port speed for most desktops and many carrier handoffs; faster versions such as 10GigE are common for uplinks.
- Both ends of a link must support the same physical standard, so the provider’s handoff must match your equipment.
What problem it solves
Ethernet is the common language of local networks, and Gigabit Ethernet made 1 Gbps an affordable everyday speed for computers, switches and routers. For buyers, it matters most where two networks meet: the point where a carrier hands a service to your router or firewall. That handoff has to match in speed, connector, optic type and settings, or the circuit does not come up.
Knowing what Gigabit Ethernet is also helps decode quotes. A “1G DIA” quote might mean a 1 Gbps port with a full 1 Gbps commitment, or a 1 Gbps port with a smaller committed rate. A “1G private line” may be an Ethernet private line delivered on a GigE interface at each end. The port tells you the ceiling; the contract tells you what is committed.
How it works
Copper. 1000BASE-T carries 1 Gbps over four pairs of twisted-pair cable using RJ-45 connectors, up to 100 meters. Most office cabling installed in recent decades supports it, though old or damaged runs may negotiate down to 100 Mbps.
Fiber. Fiber versions use optical transceivers, often small form-factor pluggable (SFP) modules. Short-reach optics such as 1000BASE-SX typically use multimode fiber inside a building or campus. Long-reach optics such as 1000BASE-LX and longer-reach variants typically use single-mode fiber between buildings or to a carrier. Both ends need compatible optics and the right fiber and connector type.
Negotiation and settings. Copper ports usually auto-negotiate speed and duplex. Fiber handoffs may need speed, duplex, auto-negotiation and VLAN tagging set to match the provider’s configuration. Mismatches are a common cause of slow or failing turn-ups.
Inside the network. A network switch with GigE ports connects users and devices; uplinks between switches and to the core often run at 10 Gbps or faster to avoid bottlenecks.
At the carrier edge. Providers deliver services such as dedicated internet access on a GigE port and may set a committed rate below the port speed. Measured throughput is also reduced by protocol overhead, so a speed test on a 1 Gbps link typically shows somewhat less than 1,000 Mbps.
To compare internet services delivered on GigE and faster ports, see our Dedicated Internet Access solution page.
When it matters for buyers
- Ordering a circuit. Specify the handoff: copper or fiber, optic type, connector and whether the port is GigE or 10GigE.
- Sizing a site. Decide whether 1 Gbps is enough for today’s usage and expected growth, or whether a 10 Gbps port with room to upgrade the commitment makes sense.
- Refreshing equipment. Check that firewalls and routers can actually process traffic at the full port speed with security features turned on.
- Troubleshooting slow speeds. Speed or duplex mismatches, old cabling and firewall throughput limits are frequent causes.
Questions to ask vendors
- Is the handoff copper or fiber, and which optic and connector type will you install?
- What is the committed rate on this port, and can we raise it without changing the port?
- If we outgrow 1 Gbps, can you upgrade to 10 Gbps, and does that need new equipment or a new install?
- What speed, duplex and VLAN settings should our equipment use?
- Who supplies the optic on our side, and which models are supported?
- Is your demarcation equipment rated for full line-rate throughput?
How it differs from Carrier Ethernet
Gigabit Ethernet is a physical speed and interface standard: how bits move at 1 Gbps between two pieces of equipment. Carrier Ethernet is a family of services that providers sell over their networks, such as point-to-point private lines and multipoint networks, defined by bandwidth commitments, service levels and how traffic is carried between sites. A Carrier Ethernet service is often handed off on a GigE or 10GigE port, but the service rate, reach and terms come from the contract, not from the port standard. 10 Gigabit Ethernet and 100G are related, faster members of the Ethernet family, not other names for GigE.