Results for "vlan"

One switch behaving as several, and four bytes that carry the arrangement to the next switch. Here is the mechanism, the configuration, the attack the defaults invite, and a numbering plan worth copying.

A VLAN divides a switch and a VRF divides a router. Here is what that buys, the two very different ways it gets deployed, and the one use that belongs in every ordinary network.

Two VLANs on one switch cannot reach each other, and that is the design rather than a fault. Three ways to put the path back, the one that sends every packet up a cable and down again, and the command everybody forgets.

Sixteen million segments, a layer 2 network that crosses routers, and fifty bytes of wrapper that break a fabric nobody configured for them. Here is the encapsulation, the control plane, and the mistake.

A logical network diagram answers what can reach what. A physical one answers where it is and which cable connects it. One drawing cannot do both, and a framework like CIS treats a stale diagram as a missing one.

It replaces the wiring closet and the tone probe, it lets an IP phone find its own voice VLAN, and it hands the switch model and management address to anything plugged into a transmitting port.

An Ethernet port at every site, and a connection between them that the provider runs and you never see inside. The three shapes, the port or the VLAN, and the two rates that decide what you are really paying for.

Most of the time lost on a network fault goes before any command is run, on assuming which layer broke. An order removes the assumption and the first step that fails answers the question.

A switch builds this table without being configured, from the source address of every frame it sees. That one mechanism explains flooding, the commonest switch attack, and the fastest way to locate a machine.

Is it up, why is it slow, and what changed are three questions with three different data sources, and they arrive in one console. Most products are sold on the cheapest of the three.

Network automation is usually discussed as a choice of tool. What decides how safe it is sits underneath: whether the software parses a command line, or works through NETCONF or RESTCONF against a YANG model that can sta...

An ethernet frame is a fixed sequence of fields: two MAC addresses, a type or length, the payload, and a frame check sequence. Here is every field, its size, and what it does.

One serves files, the other serves blocks, and every difference in cost, speed and complexity follows from that. Here is which side of the line your workload sits on, and what a SAN costs beyond the array.

Both versions of IP have an address that works only on the local segment. In one of them it is a fault report and in the other it is required infrastructure, which is how a working network gets declared broken.

Every page on this command is a list of switches, and the switches are in the vendor reference already. The part worth writing down is how to read the address, because four shapes account for most of the calls.

Most people meet IGMP because multicast is flooding every port, or because a stream worked for four minutes and died. Both symptoms are the same mechanism seen from opposite sides.

The split is not theory. It explains why a switch at full CPU can still forward, why a ping flood can take down routing, and what happens when a controller goes away.

The radio is the first of four steps between a device and the internet. The other three are the ordinary wired network, which is why most reports of bad Wi-Fi are not about Wi-Fi.

The formal definition is geographic and dates from 1996. What survived is the broadcast domain, which is why one building holds many LANs and one LAN can cross an ocean.

Offices add switches as they grow and almost never add routers. Most of the confusion, and the classic mistake of buying a second router for its ports, comes from not knowing why.