IPIP tunnel (protocol 4 vs protocol 94)
Hi,
am just really
curious about the difference between the two IPIP tunneling protocols namely IP
Protocol 4 (IPIP) and IP Protocol 94 (KA9Q/NOS compatible IPIP).
I've read that 94 is
the older one, but I want to know the difference in their operation. It's very
poorly documented in the internet. Also, some CCIE instructors mention that
IPIP tunnel is protocol 94 and some say it is protocol 4.
In the IOS it names
protocol 4 as "IP in IP" and protocol 94 as "NOS",
Router(config)#ip
access-list extended TEST
Router(config-ext-nacl)#10
permit ?
<0-255> An IP protocol number
ahp
Authentication Header Protocol
eigrp
Cisco's EIGRP routing protocol
esp
Encapsulation Security Payload
gre
Cisco's GRE tunneling
icmp
Internet Control Message Protocol
igmp
Internet Gateway Message Protocol
ip
Any Internet Protocol
ipinip IP in IP tunneling
nos KA9Q NOS compatible
IP over IP tunneling
object-group
Service object group
ospf
OSPF routing protocol
pcp
Payload Compression Protocol
pim
Protocol Independent Multicast
tcp
Transmission Control Protocol
udp
User Datagram Protocol
Router(config-ext-nacl)#10
permit 4 any any
Router(config-ext-nacl)#20
permit 94 any any
Router(config-ext-nacl)#
Router(config-ext-nacl)#do
sh ip access
Extended IP access
list TEST
10 permit ipinip any any
20 permit nos any any
Router(config-ext-nacl)#
Router(config-ext-nacl)#
Router(config-ext-nacl)#
Router(config-ext-nacl)#
Router(config-ext-nacl)#interface
tunnel 1
Router(config-if)#
Router(config-if)#tunnel
mode ?
aurp
AURP TunnelTalk AppleTalk encapsulation
cayman
Cayman TunnelTalk AppleTalk encapsulation
dvmrp
DVMRP multicast tunnel
eon
EON compatible CLNS tunnel
gre
generic route encapsulation protocol
ipip IP over IP encapsulation
ipsec
IPSec tunnel encapsulation
iptalk
Apple IPTalk encapsulation
ipv6
Generic packet tunneling in IPv6
ipv6ip
IPv6 over IP encapsulation
mpls
MPLS encapsulations
nos IP over IP encapsulation
(KA9Q/NOS compatible)
rbscp
RBSCP in IP tunnel
Regards,
Carlos
Comments
Hi Carlos,
I don't know the exact difference between them, but nowadays whenever talking about IPinIP in Cisco's realm, you are going to use protocol number 4 for IPv4 and 41 for IPv6.
I guess protocol number 94 is used for some sort of backwards compatibility.
HTH
Good luck!
Thanks qqabdal,