Example for Configuring Centralized MAP-T

This section provides an example for configuring the centralized MAP-T function on a device functioning as a MAP-BR.

Networking Requirements

In a centralized scenario shown in Figure 1, the MAP-BR and BRAS reside on different devices. The BRAS delivers MAP addresses and mapping rules to MAP-CEs in DHCPv6 IA_PD mode. (In this example, only key BRAS configurations are provided. For details about IPv6 address assignment configuration, see HUAWEI NetEngine 8000 F SeriesRouter Configuration Guide - User Access - IPv6 Address Management Configuration.) RouterA (MAP BR) resides on the edge of a MAP domain and allows MAP-CEs to access the public IPv4 network through the IPv6 network that is within the MAP domain. The MAP-CEs can also communicate with each other through the MAP-BR based on each other's public IPv4 address.

Figure 1 MAP-T networking

In this example, interface 1 and interface 2 are GE 0/1/8 and GE 0/1/9, respectively.

Prerequisites

The MAP function has been activated.
The MAP-BR has at least one interface board that supports the MAP function.

Configuration Roadmap

The configuration roadmap is as follows:

Configure a BMR.
Configure a DMR prefix address and a prefix length.
Configure an IPv6 prefix pool and an address pool on the BRAS.
Configure a MAP-T instance and bind the DMR and BMR rules to the MAP-T instance.

Data Preparation

To complete the configuration, you need the following data:

BMR name (bmr_name), IPv6 address (2001:db8:1::1), prefix length (48 bits), IPv4 address (1.1.1.0), mask (24), EA length (16 bits), and PSID offset (4)
DMR name (dmr_name), IPv6 address (2001:db8:3::1), and prefix length (96 bits)
MAP-T instance name (1) and ID (1)
Interface1's IPv6 address (2001:db8:2::1) and mask length (64 bits).
Interface2's IPv4 address (11.1.1.1) and mask length (24 bits)

Procedure

Configure a BMR on the BRAS to instruct the BRAS to assign IPv6 and IPv4 addresses to the MAP-CEs. In this example, the IPv6 prefix address assigned to the MAP-CE is 2001:db8:1::1, the prefix length is 48, and the length of the EA-bits is 16. The public IPv4 prefix address allocated to the MAP-CE is 1.1.1.0 and the prefix length is 24. The offset length of the PSID field is 4, which means that ports 0 to 4096 are reserved.
```
<BRAS> system-view
[~BRAS] map rule bmr_name
[*BRAS-map-rule-bmr_name] rule-prefix 2001:db8:1::1 prefix-length 48 ipv4-prefix 1.1.1.0 prefix-length 24 ea-length 16 psid-offset 4
[*BRAS-map-rule-bmr_name] commit
[~BRAS-map-rule-bmr_name] quit
```
Configure a DMR rule on the BRAS and combine the IPv6 prefix configured in the DMR rule with the destination IPv4 address on a MAP-CE to form a destination IPv6 address.
```
[~BRAS] dmr-prefix dmr_name ipv6-prefix 2001:db8:3::1 prefix-length 96
[*BRAS] commit
```
Configure an IPv6 prefix pool and an address pool on the BRAS.
- Configure an IPv6 prefix pool named pre1, bind it to the MAP rule named bmr_name, and assign IPv4 and IPv6 addresses that comply with BMR rules.
```
[~BRAS] ipv6 prefix pre1 delegation
[*BRAS-ipv6-prefix-pre1] map-rule bmr_name
[*BRAS-ipv6-prefix-pre1] commit
[~BRAS-ipv6-prefix-pre1] quit
```
- Configure an IPv6 address pool named pool1 and bind it to the prefix pool named pre1. Bind the prefix dmr_name to the IPv6 address pool so that the BRAS encapsulates the IPv6 prefix into Option 91 information (OPTION_S46_DMR) carried in the DHCPv6RESPONSE packet sent to MAP-CEs.
```
[~BRAS] ipv6 pool pool1 bas delegation
[*BRAS-ipv6-pool-pool1] prefix pre1
[*BRAS-ipv6-pool-pool1] option-s46 dmr-prefix dmr_name
[*BRAS-ipv6-pool-pool1] commit
[~BRAS-ipv6-pool-pool1] quit
```

Configure BMRs on the MAP-BR. Configure the BMR to remove the user-side IPv4 address from the IPv6 address and encapsulate IPv6 information into the IPv4 address and port number of the network-side traffic.

<RouterA> system-view
[~RouterA] map rule bmr_name
[*RouterA-map-rule-bmr_name] rule-prefix 2001:db8:1::1 prefix-length 48 ipv4-prefix 1.1.1.0 prefix-length 24 ea-length 16 psid-offset 4
[*RouterA-map-rule-bmr_name] commit
[~RouterA-map-rule-bmr_name] quit

Configure a DMR on the MAP-BR.

[~RouterA] dmr-prefix dmr_name ipv6-prefix 2001:db8:3::1 prefix-length 96
[*RouterA] commit

Configure a MAP-T instance on the MAP-BR and bind the configured DMR and BMR rules to the MAP-T instance. The DMR rule is used to translate the IPv6 packets imported from the MAP-CE to the MAP-T instance for address translation and bind the BMR rules to encapsulate and verify the packets in the instance.
```
[~RouterA] map-t instance 1 id 1
[*RouterA-map-t-instance-1] dmr-prefix dmr_name
[*RouterA-map-t-instance-1] map-rule bmr_name
[*RouterA-map-t-instance-1] commit
[~RouterA-map-t-instance-1] quit
```

Configure IP addresses of the user- and network-side interfaces on the MAP-BR.

[~RouterA] interface GigabitEthernet0/1/8
[~RouterA-GigabitEthernet0/1/8] ipv6 enable
[*RouterA-GigabitEthernet0/1/8] ipv6 address 2001:db8:2::1 64
[*RouterA-GigabitEthernet0/1/8] commit
[~RouterA-GigabitEthernet0/1/8] quit
[~RouterA] interface GigabitEthernet0/1/9
[~RouterA-GigabitEthernet0/1/9] ip address 11.1.1.1 24
[*RouterA-GigabitEthernet0/1/9] commit
[~RouterA-GigabitEthernet0/1/9] quit
[~RouterA] ipv6 route-static 2001:db8:1::1 48 2001:db8:2::2
[*RouterA] commit

Configure an address for the interface connecting the BRAS to the MAP-BR device.

[~BRAS] interface GigabitEthernet0/1/8
[*BRAS-GigabitEthernet0/1/8] ipv6 enable
[*BRAS-GigabitEthernet0/1/8] ipv6 address 2001:db8:2::2 64
[*BRAS-GigabitEthernet0/1/8] undo shutdown
[*BRAS-GigabitEthernet0/1/8] commit
[~BRAS-GigabitEthernet0/1/8] quit
[~BRAS] ipv6 route-static 2001:db8:3::1 48 2001:db8:2::1
[*BRAS] commit

Router A Configuration File (MAP-BR)

#
dmr-prefix dmr_name ipv6-prefix 2001:db8:3::1 prefix-length 96
#
map rule bmr_name
 rule-prefix 2001:db8:1::1 prefix-length 48 ipv4-prefix 1.1.1.0 prefix-length 24 ea-length 16 psid-offset 4
#
map-t instance 1 id 1
 dmr-prefix dmr_name
 map-rule bmr_name
#
interface GigabitEthernet0/1/8
 undo negotiation auto
 undo shutdown
 ipv6 enable
 ipv6 address 2001:db8:2::1/64
#
interface GigabitEthernet0/1/9
 undo negotiation auto
 undo shutdown
 control-flap
 ip address 11.1.1.1 255.255.255.0
#
ipv6 route-static 2001:db8:1::1 48 2001:db8:2::2
#

BRAS Configuration File

#
dmr-prefix dmr_name ipv6-prefix 2001:db8:3::1 prefix-length 96
#
map rule bmr_name
 rule-prefix 2001:db8:1::1 prefix-length 48 ipv4-prefix 1.1.1.0 prefix-length 24 ea-length 16 psid-offset 4
#
ipv6 prefix pre1 delegation
 map rule bmr_name
ipv6 pool pool1 bas delegation
 prefix pre1
 option-s46 dmr-prefix dmr_name
#
interface GigabitEthernet0/1/8
 undo shutdown
 ipv6 enable
 ipv6 address 2001:db8:2::2/64
#
ipv6 route-static 2001:db8:3::1 48 2001:db8:2::1
#