ASR 1000 Box-to-Box NAT High Availability Configuration Example

Introduction

This document describes the configuration for Box-to-Box-NAT High Availability (B2B NAT HA) on Cisco IOS^®-XE devices, with the focus on the Aggregation Services Router (ASR)1000 family.

B2B NAT HA is a method to achieve high availability of applications such as Zone-Based Firewall (ZBFW), Network Address Translation (NAT), VPN, Session Border Controller (SBC), and so on between ASR 1000 family routers. This document describes how to configure B2B NAT HA on the Cisco ASR 1000 platform along with the verification.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• Overview knowledge of the ASR 1000 platform architecture
• Basic knowledge on High Availability and NAT technologies

Components Used

The information in this document is based on the ASR 1000 family with Cisco IOS Version XE 3.10 and later releases. B2B NAT HA is supported on Cisco IOS-XE Release 3.5 and later.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Configure

B2BHA Failover Triggers

Some of the common failover triggers are:

• Power loss/reload (this includes crashes)on the active.
• Reload of Embedded Service Processor (ESP) (either planned or unplanned).
• Control interface for Redundancy Group (RG) is shutdown/link down.
• Data interface for RG is shutdown/link down.
• Tracked Object Failure (IP Service Level Agreement).
• Protocol keep-alive failure.
• The run-time priority of the active goes down below that of the threshold configured.
• The run-time priority of the active goes down below that of the standby.

Minimum Configuration

This section describes how to configure B2B NAT HA along with topology information.

B2 BHA deployments could have these three topologies:

• LAN-LAN
• LAN-WAN
• LAN Mesh

Note: The average redundancy packet size is 256 bytes.

Network Diagram with Basic L2/L3 Connectivity

Basic L2/L3 Connectivity

Configuration could be divided in two major parts. One part is the basic configuration that enables RG, redundancy protocol, timers, control, and data interfaces. The second part relates to the actual data/traffic interfaces and its association with RG.

This example tries to achieve B2B NAT HA on the ASR with the far-end server 192.168.5.5 from the LAN 172.16.1.4. These configurations are prepared with STATIC NAT configuration at the moment.

ip nat pool POOL1 200.200.200.200 200.200.200.200 netmask 255.255.255.252
ip nat inside source list NAT pool POOL1 redundancy 1 mapping-id 252

Extended IP access list NAT
    10 permit ip host 172.16.1.4 host 192.168.5.5

ASR-1 

redundancy
 mode none
 application redundancy
 group 1
 name TEST
 preempt
 priority 150
 control GigabitEthernet0/0/2

 protocol 1
 data GigabitEthernet0/0/3

ASR-2
    
redundancy
mode none
application redundancy
group 1
name TEST
preempt
priority 50
control GigabitEthernet0/0/2

protocol 1
data GigabitEthernet0/0/3

Both the ASRs should be able to reach the public IP address provided by the ISP.

ASR-1#ping 200.200.200.200
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.200.200.200, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

ASR-2#ping 200.200.200.200
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.200.200.200, timeout is 2 seconds:
!!!!!

The LAN Facing interface is connected to the distribution switches, which are in turn connected to the hosts.

ASR-1#show run int GigabitEthernet0/0/0
interface GigabitEthernet0/0/0
 ip address 172.16.1.2 255.255.255.248
 ip nat inside
 negotiation auto
 cdp enable
 redundancy rii 100
 redundancy group 1 ip 172.16.1.5
  exclusive decrement 100
end

ASR-2#show run int GigabitEthernet0/0/0
interface GigabitEthernet0/0/0
 ip address 172.16.1.3 255.255.255.248
 ip nat inside
 negotiation auto
 cdp enable
 redundancy rii 100
 redundancy group 1 ip 172.16.1.5
  exclusive decrement 100
end

The ISP Facing interface has this configuration:

ASR-1#show run int gi0/0/1
interface GigabitEthernet0/0/1
 ip address 192.168.3.2 255.255.255.252
 ip nat outside
 negotiation auto
 cdp enable
 redundancy rii 101
 redundancy asymmetric-routing enable
 redundancy group 1 decrement 20
end

ASR-2#show run int gi0/0/1
interface GigabitEthernet0/0/1
 ip address 192.168.4.2 255.255.255.252
 ip nat outside
 negotiation auto
 cdp enable
 redundancy rii 101
 redundancy asymmetric-routing enable
 redundancy group 1 decrement 20
end

The Data and the Control interfaces between the ASRs have been configured as shown in these sections.

Control Interface

ASR-1#show run int gi0/0/2
interface GigabitEthernet0/0/2
description CONTROL-INTERFACE
ip address 10.10.10.1 255.255.255.252
negotiation auto
cdp enable
end

ASR-2#show run int gi0/0/2
interface GigabitEthernet0/0/2
description CONTROL INTERFACE
ip address 10.10.10.2 255.255.255.252
negotiation auto
cdp enable
end

Data Interface

ASR-1#show run int gi0/0/3
interface GigabitEthernet0/0/3
description DATA INTERFACE
encapsulation dot1Q 10
ip address 10.11.11.1 255.255.255.252
end

ASR-2#show run int gi0/0/3
interface GigabitEthernet0/0/3
description DATA INTERFACE
encapsulation dot1Q 10
ip address 10.11.11.2 255.255.255.252
end

Note:
- You must not configure a redundant interface identifier (RII) on an interface that is configured either as a data interface or as a control interface.
- You must configure the RII and asymmetric routing on both active and standby devices.
- You cannot enable asymmetric routing on the interface that has a virtual IP address configured.

Verify

Verification Commands and Expected Output

The Cisco CLI Analyzer  (registered customers only) supports certain show commands. Use the Cisco CLI Analyzer in order to view an analysis of show command output.

ASR-1#show redundancy application group 
Group ID    Group Name                      State
--------    ----------                      -----
1           TEST                           ACTIVE

ASR-2#show redundancy application group
Group ID    Group Name                      State
--------    ----------                      -----
1           TEST                           STANDBY

ASR-1#show redundancy application group 1
Group ID:1
Group Name:TEST

Administrative State: No Shutdown
Aggregate operational state : Up
My Role: ACTIVE
Peer Role: STANDBY
Peer Presence: Yes
Peer Comm: Yes
Peer Progression Started: Yes

RF Domain: btob-one
     RF state: ACTIVE
     Peer RF state: STANDBY HOT

ASR-2#show redundancy application group 1
Group ID:1
Group Name:TEST

Administrative State: No Shutdown
Aggregate operational state : Up
My Role: STANDBY
Peer Role: ACTIVE
Peer Presence: Yes
Peer Comm: Yes
Peer Progression Started: Yes

RF Domain: btob-one
     RF state: STANDBY HOT
     Peer RF state: ACTIVE

ASR-1#show ip nat translations 
Pro  Inside global         Inside local          Outside local         Outside global
---  200.200.200.200       172.16.1.4            ---                   ---
icmp 200.200.200.200:98    172.16.1.4:98         192.168.5.5:98        192.168.5.5:98
Total number of translations: 2

ASR-2#show ip nat translations 
Pro  Inside global         Inside local          Outside local         Outside global
---  200.200.200.200       172.16.1.4            ---                   ---
icmp 200.200.200.200:98    172.16.1.4:98         192.168.5.5:98        192.168.5.5:98
Total number of translations: 2

ASR-1#show redundancy application protocol group 1

RG Protocol RG 1
------------------
    Role: Active
    Negotiation: Enabled
    Priority: 150
    Protocol state: Active
    Ctrl Intf(s) state: Up
    Active Peer: Local
    Standby Peer: address 10.10.10.2, priority 50, intf Gi0/0/2
    Log counters:
        role change to active: 7
        role change to standby: 7
        disable events: rg down state 7, rg shut 0
        ctrl intf events: up 7, down 8, admin_down 7
        reload events: local request 0, peer request 0

RG Media Context for RG 1
--------------------------
    Ctx State: Active
    Protocol ID: 1
    Media type: Default
    Control Interface: GigabitEthernet0/0/2
        Current Hello timer: 3000
    Configured Hello timer: 3000, Hold timer: 9000
    Peer Hello timer: 3000, Peer Hold timer: 9000
    Stats:
        Pkts 386597, Bytes 23969014, HA Seq 0, Seq Number 386597, Pkt Loss 0
        Authentication not configured
        Authentication Failure: 0
        Reload Peer: TX 0, RX 0
        Resign: TX 0, RX 1
    Standby Peer: Present. Hold Timer: 9000
        Pkts 386589, Bytes 13144026, HA Seq 0, Seq Number 1503658, Pkt Loss 0

ASR-2#show redundancy application protocol group 1

RG Protocol RG 1
------------------
    Role: Standby
    Negotiation: Enabled
    Priority: 50
    Protocol state: Standby-hot
    Ctrl Intf(s) state: Up
    Active Peer: address 10.10.10.1, priority 150, intf Gi0/0/2
    Standby Peer: Local
    Log counters:
        role change to active: 8
        role change to standby: 16009
        disable events: rg down state 1, rg shut 0
        ctrl intf events: up 9, down 10, admin_down 1
        reload events: local request 15999, peer request 2

RG Media Context for RG 1
--------------------------
    Ctx State: Standby
    Protocol ID: 1
    Media type: Default
    Control Interface: GigabitEthernet0/0/2
        Current Hello timer: 3000
    Configured Hello timer: 3000, Hold timer: 9000
    Peer Hello timer: 3000, Peer Hold timer: 9000
    Stats:
        Pkts 1503674, Bytes 93227788, HA Seq 0, Seq Number 1503674, Pkt Loss 0
        Authentication not configured
        Authentication Failure: 0
        Reload Peer: TX 2, RX 2
        Resign: TX 8, RX 7
    Active Peer: Present. Hold Timer: 9000
        Pkts 386603, Bytes 13144502, HA Seq 0, Seq Number 386613, Pkt Loss 0

ASR-1#show platform hardware qfp active system rg 1
Redundancy Group 1
    State:        RG_ACTIVE
    Bulksync:    NO BULKSYNC REQ
    Transport:    
        SYNC_B2B    LISTEN
            cp hdl 0x01013e8d dp hdl 0x03010006, platfm hdl 0x0000fa35
        L3_IPV4
            src addr 10.11.11.1    dest addr 10.11.11.2
        L4_UDP_RELIABLE
            src port   19510    dest port   3497

        AR transport not available
    Stats:
        RG Request:
            CREATE        0
            UPDATE        32048
            DELETE        0
        RG State:
            RG_PREINIT        0
            RG_INIT            7
            RG_STANDBY        21
            RG_ACTIVE        32020
        RG Transport Request:
                    NA            0
            OPEN            16014
            CLOSE            0
        RG Transport Status:
            CONN_ESTB        7
            CONN_FAIL        0
            TRANS_DOWN        0
            TRANS_DOWN_GRACEFUL    8
        Bulksync:
            Request            7
            Success            7
            Fail            0

ASR-1#show platform hardware qfp active system rg 1 stats 
    trans index:    00000006  Trans Type:    00000001  RG    1
    mf_flags    0x40000000  seq_flags    0x700003ff
    ha_control_state    0x5
    pending ack        00000000
    keepalive_timeout    00000100
    rx_seq_flags        0x8000000
    rx_seq_num    0x2c0d4a44
    tx_seq        0xb4965908
    tx_ack_tail    0xb4965908
    tx_seq_flags    0x700003ff
    tx    0000000000580126
    rx    0000000000580089
    retx    0000000000000000
    rx dropped    0000000000000000
    records dropped    0000000000000000
    tx dropped    0000000000000000
    ack dropped    00000000  oob pkts dropped 00000000
    send dropped 00000000  rx_control_msgs 00580090
    tx control_msgs 00580078   for_us_hits 01160217
    sync_alloc_failures 00000000  status_notifications 00000001
    sync_msgs_received 00580093  sync_msgs_sent 00580133
    for_us_udp_checksum_drops 00000000
    acks sent 00580089 rcvd 00580126  nacks sent 00000000 rcvd 00000000

Useful Commands

• RG on active is reloaded with the redundancy application reload group <rg-number> self command in exec mode.
• RG on active is shut down with the use of these CLI commands in redundancy config mode:

  ISR1(config-red-app)#group 1
  ISR1(config-red-app-grp)#shutdown

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.