Ethernet administrative and operational encapsulation

Switchport - IEEE 802.1q

Switchport trunk encapsulation


Inter-Switch Link or ISL is a Cisco proprietary protocol that maintains [VLAN](/vlan) information on [Ethernet](/ethernet) frames that traverse a [trunk](/switchport-trunk) link between switches

ISL is a type of [trunk encapsulation](/switchport-trunk-encapsulation) that adds a VLAN ID to the [Ethernet header](/ethernet-header).  It is no longer available in newer switches and has been largely superseded by the [IEEE 802.1Q](/switchport-ieee-8021q) standard.

Links:

https://forum.networklessons.com/t/how-to-configure-trunk-on-cisco-catalyst-switch/869/104?u=lagapides

Switchport - ISL

Security - accessing VTY from another VRF

Security - assigning privilege levels, syntax and behavior

Security - bogons

Security - broadcast-multicast storm

Security - configuring TACACS from another VRF

Security - privilege levels and command output

Security - privilege levels and enable keyword

Security - public key exchange

Security - root CAs and private keys

Security - spoofing

Security - storm control algorithm

Security IKE policy hash command

Security Trusted Platform Module (TPM)

Security aaa new-model

Security authentication on VTY lines

Security keyrings

Segment Routing

Serial Interface default broadcast address

Session Border Controller

Session Initiation Protocol

Show open TCP-UDP ports on Cisco router

Spanning Tree Protocol (STP)

Spine and leaf architecture - connections to leaf switches

Spine and leaf architecture - connections to spine switches

Spine and leaf architecture - reducing latency

Split-horizon

StackWise Virtual

Stackwise election process

Stackwise user priority

Subscriber templating

Summarization

Supernetting

Switch configuring a routed port

Switch high availability options

Switch protected port limitations

Switch protected port

Switching - CEF

Switching - Media Access Control (MAC) addresses

Switching - Process switching

Switching - backplane

Switching - cut through

Switching - fast switching

Switching - show cable-diagnostics

Switching - store and forward

Switching - switch fabric

Switching - switched virtual interface (SVI)

Switching - switchport autostate command

Switching

Switchport access

Switchport modes

Switchport trunk configuration ignores access commands

Switchport trunk

Symmetric Digital Subscriber Line (SDSL)

Syslog - terminal monitor

Syslog relay or proxy

Syslog severity levels

TCP - Congestion control

TCP - Header

TCP - SEQ and ACK values

TCP - Slow start

TCP - Three-way handshake

TCP - Urgent pointer field

TCP - Window Size Scaling

TCP - factors affecting segment size

TCP - role of checksum field

TCP MSS and window size

TCP RST flag

TCP SYN timeout

TCP header options

TCP phantom byte

TCP-IP model

TFTP

Tcl Shell

Telnet

Time to live

Traceroute - Interpreting output

Traceroute asterisk and !H responses

Traceroute

Transparent Cisco IOS Firewall use cases

Transport Layer port number

Troubleshooting - using Telnet to test transport layer ports

Troubleshooting a slow network

Troubleshooting high CPU and memory usage on a switch

UDP - Header

UDP - Maximum Datagram Size

Unicast Reverse Path Forwarding (uRPF)

Unicast traffic

Unknown unicast traffic

Upgrade your R&S skills to modern networking

VACL - Changes to ACL are active immediately

VLAN - Extended Range

VLAN - Native VLAN best practices

VLAN - Native VLAN on a router on a stick

VLAN - Private VLAN

VLAN - VLAN IDs 0 and 4095

Switchport - ISL

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