SONiC IP/LAG Incremental Update

Table of Contents

Revision
RevDateAuthorChange Description
0.12018-09Shuotian ChengInitial Version

About

This document provides the general information about basic SONiC incremental configuration support including IP addresses configuration changes, and port channel configuration changes.

1. Requirements Overview

1.1 Functional Requirements

Phase #0

  • Should be able to boot directly into working state given a working minigraph

  1. All IPs are assigned correctly to each router interfaces

  2. All port channel interfaces are created with correct members enslaved

  3. All VLAN interfaces are created with correct members enslaved

  4. All configured ports are set to admin status UP

  5. All configured ports are set to desired MTU

Phase #1

  • Should not have static front panel interface configurations in /etc/network/interfaces file

  • Should not have static teamd configurations in /etc/teamd/ folder.

  • Should be able to use command line to execute incremental updates including:

  1. Bring up/down all ports/port channels/VLANs

  2. Assign/remove IPs towards non-LAG-member/non-VLAN-member front panel ports, and port channels

  3. Create/remove port channels

  4. Add/remove members of port channels

  • Should be able to restart docker swss and the system recovers to the state before the restart

Note:​

  1. Conflicting configurations that cannot be directly resolved areNOT supported in this phrase, including:​

  • moving a port with IP into a port channel

  • assign an IP to a port channel member

  • adding/removing non-existing ports towards port channels, etc.​

  1. Port channel and port channel members' admin status are controlled separately, indicating that a port channel's admin status DOWN will NOT affect its members' admin status to be brought down as well.​

  2. Admin status and MTU are must have attributes for ports and port channels, and the default values are UP and 9100.​

  3. MTU will be changed to the port channel's MTU once a port is enslaved into the port channel. However, the value will be automatically reset to its original one after the port is removed from the port channel.​

Phase #2

  • Should be able to move loopback interface out of /etc/network/interfaces file and managed by portmgrd.

  • Should be able to restart docker teamd and all port channel configurations are reapplied

Note:​ The reason of moving this request into phase 2 is due to unrelated issues encountered while removing and recreating router interfaces, including IPv6 removal and potential SAI implementation issues.​

Future Work

TBD

1.2 Orchagent Requirements

The gap that orchagent daemon needs to fill is mostly related to MTU:

  • Should be able to change router interface MTU

  • Should be able to change LAG MTU

1.3 *-syncd Requirements

  • portsyncd: Should not be listening to netlink message to get port admin status and MTU

1.4 *-mgrd Requirements

  • portmgrd: Should be responsible for admin status and MTU configuration changes. Related tables: PORT

  • intfsmgrd: Should be responsible for port/port channel/VLAN IP configuraton changes. Related tables: PORT_INTERFACE, PORTCHANNEL_INTERFACE, VLAN_INTERFACE.

  • teammgrd: Should be responsible for port channel and port channel member configuration changes. Related tables: PORTCHANNEL AND PORTCHANNEL_MEMBER.

1.4 Utility Requirements

config interface <interface_name> add ip <ip_address>
config interface <interface_name> remove ip <ip_address>
config interface <interface_name> mtu <mtu_value>

config port_channel add <port_channel_name>
config port_channel remove <port_channel_name>
config port_channel member add <port_channel_name> <port_name>
config port_channel member remove <port_channel_name> <port_name>

2. Database Design

2.1 CONF_DB

2.1.1 PORT Table

PORT|{{port_name}}
  "admin_status": {{UP|DOWN}}
  "mtu": {{mtu_value}}

2.1.2 INTERFACE Table

INTERFACE|{{port_name}}|{{IP}}

2.1.3 PORTCHANNEL Table

PORTCHANNEL|{{port_channel_name}}
  "admin_status": {{UP|DOWN}}
  "mtu": {{mtu_value}}
  "min_links": {{min_links_value}}
  "fall_back": {{true|false}}

2.1.4 PORTCHANNEL_INTERFACE Table

PORTCHANNEL_INTERFACE|{{port_channel_name}}|{{IP}}

2.1.5 PORTCHANNEL_MEMBER Table

PORTCHANNEL_MEMBER|{{port_channel_name}}|{{port_name}}

3. Daemon Design

3.1 orchagent

  • When LAG MTU is updated, all LAG members' MTUs are updated.

  • When port/LAG MTU is updated, the associated router interface MTU is updated.

3.2 portmgrd

  • Monitor PORT table

  • Should be responsible for admin status changes and MTU changes

3.3 intfsyncd

  • Monitor PORT_INTERFACE, PORTCHANNEL_INTERFACE, VLAN_INTERFACE tables

  • Should be responsible for IP changes

3.4 teamsyncd

  • Monitor PORTCHANNEL and PORTCHANNEL_MEMBER tables

  • Should be responsible for port channel changes and member changes

4. Flows

4.1 Admin Status/MTU Configuration Flow

4.2 Port Channel and Member Configuration Flow

4.3 IP Configuration Flow

4.4 Device Start Flow

4.5 Docker swss Restart

TBD

4.6 Docker teamd Restart

TBD