Layer 2 Tunneling Protocol

In computer networking, Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol used to support virtual private networks (VPNs) or as part of the delivery of services by ISPs. It does not provide any encryption or confidentiality by itself; it relies on an encryption protocol that it passes within the tunnel to provide privacy.

Internet protocols
Application layer
  • DHCP
  • DHCPv6
  • DNS
  • FTP
  • HTTP
  • IMAP
  • IRC
  • LDAP
  • MGCP
  • NNTP
  • NTP
  • POP
  • RPC
  • RTP
  • RTSP
  • SIP
  • SMTP
  • SNMP
  • SOCKS
  • SSH
  • Telnet
  • TLS/SSL
  • XMPP
  • (more)
Transport layer
  • TCP
  • UDP
  • DCCP
  • SCTP
  • RSVP
  • (more)
Routing protocols *
  • BGP
  • OSPF
  • RIP
  • (more)
Internet layer
  • IP
    • IPv4
    • IPv6
  • ICMP
  • ICMPv6
  • ECN
  • IGMP
  • IPsec
  • (more)
Link layer
  • ARP/InARP
  • NDP
  • Tunnels
    • L2TP
  • PPP
  • Media access control
    • Ethernet
    • DSL
    • ISDN
    • FDDI
  • (more)
* Not a layer. A routing protocol belongs either to application or network layer.

Read more about Layer 2 Tunneling Protocol:  History, Description, Tunneling Models, L2TP Packet Structure, L2TP Packet Exchange, L2TP/IPsec, Windows Implementation, L2TP in ISPs' Networks

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