To set the encapsulation mode for the tunnel interface, use the
tunnelmode command in interface configuration mode. To restore the default mode, use the no form of this command.
tunnel
mode
{ aurp | cayman | dvmrp | eon | gre | gre
multipoint | gre
ipv6 | ipip
[decapsulate-any] | ipsec
ipv4 | iptalk | ipv6 | ipsec
ipv6 | mpls | nos | rbscp }
no
tunnel
mode
Syntax Description
aurp
|
AppleTalk Update-Based Routing Protocol.
|
cayman
|
Cayman TunnelTalk AppleTalk encapsulation.
|
dvmrp
|
Distance Vector Multicast Routing Protocol.
|
eon
|
EON compatible Connectionless Network Protocol (CLNS) tunnel.
|
gre
|
Generic routing encapsulation (GRE) protocol. This is the default.
|
gre
multipoint
|
Multipoint GRE (mGRE).
|
gre
ipv6
|
GRE tunneling using IPv6 as the delivery protocol.
|
ipip
|
IP-over-IP encapsulation.
|
decapsulate-any
|
(Optional) Terminates any number of IP-in-IP tunnels at one tunnel interface.
This tunnel will not carry any outbound traffic; however, any number of remote tunnel endpoints can use a tunnel configured this way as their destination.
|
ipsec
ipv4
|
Tunnel mode is IPSec, and the transport is IPv4.
|
iptalk
|
Apple IPTalk encapsulation.
|
ipv6
|
Static tunnel interface configured to encapsulate IPv6 or IPv4 packets in IPv6.
|
ipsec
ipv6
|
Tunnel mode is IPSec, and the transport is IPv6.
|
mpls
|
Multiprotocol Label Switching (MPLS) encapsulation.
|
nos
|
KA9Q/NOS compatible IP over IP.
|
rbscp
|
Rate Based Satellite Control Protocol (RBSCP).
|
Command Default
The default is GRE tunneling.
Command Modes
Interface configuration (config-if)
Command History
Release
|
Modification
|
10.0
|
This command was introduced.
|
10.3
|
The
aurp,
dvmrp, and
ipip keywords were added.
|
11.2
|
The optional
decapsulate-any keyword was added.
|
12.2(13)T
|
The
gremultipoint keyword was added.
|
12.3(7)T
|
The following keywords were added:
-
gre
ipv6
to support GRE tunneling using IPv6 as the delivery protocol.
-
ipv6
to allow a static tunnel interface to be configured to encapsulate IPv6 or IPv4 packets in IPv6.
-
rbscp
to support RBSCP.
|
12.3(14)T
|
The
ipsecipv4 keyword was added.
|
12.2(18)SXE
|
The
gremultipoint keyword added.
|
12.2(30)S
|
This command was integrated into Cisco IOS Release 12.2(30)S.
|
12.2(25)SG
|
This command was integrated into Cisco IOS Release 12.2(25)SG.
|
12.4(4)T
|
The
ipsecipv6 keyword was added.
|
12.2(33)SRA
|
This command was integrated into Cisco IOS Release 12.2(33)SRA.
|
Cisco IOS XE Release 2.1
|
This command was introduced on Cisco ASR 1000 Series Routers.
|
15.1SY
|
This command was integrated into Cisco IOS Release 15.1SY.
|
Usage Guidelines
Source and Destination Address
You cannot have two tunnels that use the same encapsulation mode with exactly the same source and destination address. The workaround is to create a loopback interface and source packets off of the loopback interface.
Cayman Tunneling
Designed by Cayman Systems, Cayman tunneling implements tunneling to enable Cisco routers to interoperate with Cayman GatorBoxes. With Cayman tunneling, you can establish tunnels between two routers or between a Cisco router and a GatorBox. When using Cayman tunneling, you must not configure the tunnel with an AppleTalk network address.
DVMRP
Use DVMRP when a router connects to an mrouted (multicast) router to run DVMRP over a tunnel. You must configure Protocol Independent Multicast (PIM) and an IP address on a DVMRP tunnel.
GRE with AppleTalk
GRE tunneling can be done between Cisco routers only. When using GRE tunneling for AppleTalk, you configure the tunnel with an AppleTalk network address. Using the AppleTalk network address, you can ping the other end of the tunnel to check the connection.
Multipoint GRE
After enabling mGRE tunneling, you can enable the
tunnelprotection command, which allows you to associate the mGRE tunnel with an IPSec profile. Combining mGRE tunnels and IPSec encryption allows a single mGRE interface to support multiple IPSec tunnels, thereby simplifying the size and complexity of the configuration.
 Note |
GRE tunnel keepalives configured using the
keepalive command under a GRE interface are supported only on point-to-point GRE tunnels.
|
RBSCP
RBSCP tunneling is designed for wireless or long-distance delay links with high error rates, such as satellite links. Using tunnels, RBSCP can improve the performance of certain IP protocols, such as TCP and IPSec, over satellite links without breaking the end-to-end model.
IPSec in IPv6 Transport
IPv6 IPSec encapsulation provides site-to-site IPSec protection of IPv6 unicast and multicast traffic. This feature allows IPv6 routers to work as a security gateway, establishes IPSec tunnels between another security gateway router, and provides crypto IPSec protection for traffic from an internal network when being transmitting across the public IPv6 Internet. IPv6 IPSec is very similar to the security gateway model using IPv4 IPsec protection.
Examples
Cayman Tunneling
The following example shows how to enable Cayman tunneling:
Router(config
)
# interface tunnel 0
Router(config-if)# tunnel source ethernet 0
Router(config-if)# tunnel destination 10.108.164.19
Router(config-if)# tunnel mode cayman
Examples
GRE Tunneling
The following example shows how to enable GRE tunneling:
Router(config
)
# interface tunnel 0
Router(config-if)# appletalk cable-range 4160-4160 4160.19
Router(config-if)# appletalk zone Engineering
Router(config-if)# tunnel source ethernet0
Router(config-if)# tunnel destination 10.108.164.19
Router(config-if)# tunnel mode gre
Examples
IPSec in IPv4 Transport
The following example shows how to configure a tunnel using IPSec encapsulation with IPv4 as the transport mechanism:
Router(config)#
cryptoipsecprofilePROF
Router(config ) #settransformtset
Router(config ) #interfaceTunnel0
Router(config -if) #ipaddress10.1.1.1255.255.255.0
Router(config -if) #tunnelmodeipsecipv4
Router(config -if) #tunnelsourceLoopback0
Router(config -if) #tunneldestination172.16.1.1
Router(config-if)# tunnel protection ipsec profile PROF
Examples
IPSec in IPv6 Transport
The following example shows how to configure an IPv6 IPSec tunnel interface:
Router(config)# interface tunnel 0
Router(config-if)# ipv6 address 2001:0DB8:1111:2222::2/64
Router(config-if)# tunnel destination 10.0.0.1
Router(config-if)# tunnel source Ethernet 0/0
Router(config-if)# tunnel mode ipsec ipv6
Router(config-if)# tunnel protection ipsec profile profile1
Examples
Multipoint GRE Tunneling
The following example shows how to enable mGRE tunneling:
interface Tunnel0
bandwidth 1000
ip address 10.0.0.1 255.255.255.0
! Ensures longer packets are fragmented before they are encrypted; otherwise, the ! receiving router would have to do the reassembly.
ip mtu 1416
! Turns off split horizon on the mGRE tunnel interface; otherwise, EIGRP will not ! advertise routes that are learned via the mGRE interface back out that interface.
no ip split-horizon eigrp 1
no ip next-hop-self eigrp 1
delay 1000
! Sets IPSec peer address to Ethernet interface’s public address.
tunnel source Ethernet0
tunnel mode gre multipoint
! The following line must match on all nodes that want to use this mGRE tunnel.
tunnel key 100000
tunnel protection ipsec profile vpnprof
Examples
RBSCP Tunneling
The following example shows how to enable RBSCP tunneling:
Router(config
)
# interface tunnel 0
Router(config-if)# tunnel source ethernet 0
Router(config-if)# tunnel destination 10.108.164.19
Router(config-if)# tunnel mode rbscp
Related Commands
Command
|
Description
|
appletalk
cable-range
|
Enables an extended AppleTalk network.
|
appletalk
zone
|
Sets the zone name for the connected AppleTalk network.
|
tunnel
destination
|
Specifies the destination for a tunnel interface.
|
tunnel
protection
|
Associates a tunnel interface with an IPSec profile.
|
tunnel
source
|
Sets the source address of a tunnel interface.
|