- mGRE Tunnel Support over IPv6
- IP over IPv6 Tunnels
- Manually Configured IPv6 over IPv4 Tunnels
- Configuring Physical Interfaces
- Configuring Virtual Interfaces
- Implementing Tunnels
- Tunnel Route Selection
- MPLS VPN over mGRE
- IP Tunnel MIBs
- IF-MIBs
- Synchronous Ethernet (SyncE) ESMC and SSM
- 1+1 SR-APS Without Bridging
- IPv6 Rapid Deployment
- IPv6 Automatic 6to4 Tunnels
- IPv6 over IPv4 GRE Tunnels
- GRE IPv6 Tunnels
- ISATAP Tunnel Support for IPv6
- VRF-Aware Tunnels
- Ethernet over GRE Tunnels
- QoS on Ethernet over GRE Tunnels
- VRF-Aware IPv6 Rapid Deployment Tunnel
- IP Tunnel - GRE Key Entropy Support
- Finding Feature Information
- Prerequisites for IP Tunnel - GRE Key Entropy Support
- Restrictions for IP Tunnel - GRE Key Entropy Support
- Information About IP Tunnel - GRE Key Entropy Support
- How To Configure IP Tunnel - GRE Key Entropy Support
- Configuration Examples for IP Tunnel - GRE Key Entropy Support
- Additional References for IP Tunnel - GRE Key Entropy Support
- Feature Information for IP Tunnel - GRE Key Entropy Support
IP Tunnel - GRE
Key Entropy Support
The IP Tunnel - GRE Key Entropy Support feature enables load balancing of tunnel packets in the Generic Routing Encapsulation (GRE) mode of a core network.
- Finding Feature Information
- Prerequisites for IP Tunnel - GRE Key Entropy Support
- Restrictions for IP Tunnel - GRE Key Entropy Support
- Information About IP Tunnel - GRE Key Entropy Support
- How To Configure IP Tunnel - GRE Key Entropy Support
- Configuration Examples for IP Tunnel - GRE Key Entropy Support
- Additional References for IP Tunnel - GRE Key Entropy Support
- Feature Information for IP Tunnel - GRE Key Entropy Support
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for IP Tunnel - GRE Key Entropy Support
Restrictions for IP Tunnel - GRE Key Entropy Support
Information About IP Tunnel - GRE Key Entropy Support
IP Tunnel - GRE Key Entropy Support Overview
The IP Tunnel - GRE Key Entropy Support feature enables load balancing of tunnel packets in the Generic Routing Encapsulation (GRE) mode of a core network. You can configure the tunnel entropy calculation feature only on the GRE mode of the tunnel interface.
In order to configure tunnel entropy calculation using the tunnel entropy command, you must first configure a tunnel key using the tunnel key command in interface configuration mode. The tunnel key has a maximum size of 32 bits. If you configure tunnel entropy calculation, 24 bits are reserved for the GRE key and 8 bits for entropy.
Note | If you configure a GRE tunnel key of 32 bits, you cannot configure tunnel entropy calculation. You must remove the tunnel key and then configure a key of the size of 24 bits or less. To disable an already configured GRE tunnel entropy, remove the GRE tunnel key value first. |
Entropy bits are calculated by 6 tuples, which are virtual routing and forwarding (VRF) ID, source IP address, destination IP address, source port, destination port, and protocols of the private IPv4/IPv6 packets in a network.
How To Configure IP Tunnel - GRE Key Entropy Support
Configuring IP Tunnel - GRE Key Entropy Support
Perform this task to configure GRE tunnel entropy calculation:
1.
enable
2.
configure terminal
3.
interface tunnel
tunnel-number
4.
tunnel source {ipv4-addr
|
ipv6-addr
|
interface-type
interface-number
|
dynamic}
5.
tunnel destination {ipv4-addr
|
ipv6-addr
|
hostname |
dynamic}
6.
tunnel mode gre ip
7.
tunnel key
key-number
8.
tunnel entropy
9.
end
10.
show
interfaces
interface-type
interface-number
DETAILED STEPS
Configuration Examples for IP Tunnel - GRE Key Entropy Support
Examples: Configuring IP Tunnel - GRE Key Entropy Support
The following example shows how to configure tunnel entropy calculation for GRE mode of the tunnel interface:
Device> enable Device# configure terminal Device(config)# interface tunnel 21 Device(config-if)# tunnel source 10.1.1.1 Device(config-if)# tunnel destination 172.168.2.1 Device(config-if)# tunnel mode gre ip Device(config-if)# tunnel key 4683 Device(config-if)# tunnel entropy Device(config-if)# end
The following is sample output from the show interfaces tunnel command, which displays that tunnel entropy calculation is enabled with a 24-bit key:
Device# show interfaces tunnel 21 Tunnel21 is up, line protocol is up Hardware is Tunnel MTU 17864 bytes, BW 100 Kbit/sec, DLY 50000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 10.1.1.1, destination 172.168.2.1 Tunnel protocol/transport GRE/IP Key 0x124B, sequencing disabled Checksumming of packets disabled Tunnel Entropy Calculation Enabled (24-bit Key) Tunnel TTL 255, Fast tunneling enabled Tunnel transport MTU 1472 bytes Tunnel transmit bandwidth 8000 (kbps) Tunnel receive bandwidth 8000 (kbps) Last input never, output never, output hang never Last clearing of "show interface" counters 00:03:07 Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/0 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts (0 IP multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 0 packets output, 0 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 unknown protocol drops 0 output buffer failures, 0 output buffers swapped out
Additional References for IP Tunnel - GRE Key Entropy Support
Related Documents
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
|
Tunnel commands: complete command syntax, command mode, defaults, command history, usage guidelines, and examples |
Cisco IOS Interface and Hardware Component Command Reference |
Cisco IOS XE Interface and Hardware Component configuration modules |
Cisco IOS XE Interface and Hardware Component Configuration Guide |
Standards and RFCs
RFC | Title |
---|---|
RFC6790 |
The Use of Entropy Labels in MPLS Forwarding |
Technical Assistance
Description | Link |
---|---|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
Feature Information for IP Tunnel - GRE Key Entropy Support
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Feature Name |
Releases |
Feature Information |
---|---|---|
IP Tunnel - GRE Key Entropy Support |
Cisco IOS XE Release 3.11S |
The IP Tunnel - GRE Key Entropy Support feature enables load balancing of tunnel packets in the Generic Routing Encapsulation (GRE) mode of a core network. The following commands were introduced or modified: tunnel entropy tunnel key show interfaces |