Lldp on Aurora

Run a specified role in ansible

Thu, 30 Apr 2020 09:59:05 +0000

install lldpd by ansible roles

ansible layout

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[root@03e6e45a7f92 cc]# tree ansible
ansible
├── roles
│   └── lldp
│   ├── defaults
│   │   └── main.yml
│   ├── files
│   └── tasks
│   ├── disable_lldp.yml
│   ├── enable_lldp.yml
│   └── main.yml
└── site.yml

5 directories, 5 files

show the content

site.yml

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---
-  hosts: localhost
 name: lldpd installation
 roles:
 -  role: lldp
 tags: lldp

Or like this

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---
-  hosts: localhost
 name: lldpd installation
 tasks:
 -  import_role:
 name: lldp
 tags: lldp

defaults/main.yml

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---
LLDPD_VERSION: 1.0.22

tasks/main.yml

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---
-  include_tasks: enable_lldp.yml

tasks/enable_lldp.yml

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---
-  name: Retrieve lldpd source code
 get_url:
 url: https://github.com/lldpd/lldpd/releases/download/{{ LLDPD_VERSION }}/lldpd-{{ LLDPD_VERSION }}.tar.gz
 dest: /tmp/lldpd-{{ LLDPD_VERSION }}.tar.gz
-  name: Extract archive
 unarchive:
 # if configured like as the following, 'Retrieve lldpd source code' task can be removed
 # src: https://github.com/lldpd/lldpd/releases/download/{{ LLDPD_VERSION }}/lldpd-{{ LLDPD_VERSION }}.tar.gz
 src: /tmp/lldpd-{{ LLDPD_VERSION }}.tar.gz
 dest: /tmp
-  name: Configure install
 command: ./configure
 args:
 chdir: /tmp/lldpd-{{ LLDPD_VERSION }}
 creates: /tmp/lldpd-{{ LLDPD_VERSION }}/configure.status.log
-  name: Build lldpd
 command: make
 args:
 chdir: /tmp/lldpd-{{ LLDPD_VERSION }}
 creates: /tmp/lldpd-{{ LLDPD_VERSION }}/make.status.log
-  name: Install lldpd
 become: true
 command: make install
 args:
 chdir: /tmp/lldpd-{{ LLDPD_VERSION }}
 creates: /tmp/lldpd-{{ LLDPD_VERSION }}/make_install.status.log
-  name: Create chroot for lldpd
 file:
 path: /usr/local/var/run/lldpd
 state: directory
-  name: Create _lldpd group
 group:
 name: _lldpd
 state: present
-  name: Create _lldpd user
 user:
 name: _lldpd
 group: _lldpd
 comment: lldpd user
-  name: Remove build directory
 file:
 path: /tmp/lldpd-{{ LLDPD_VERSION }}
 state: absent
-  name: Remove archive
 file:
 path: /tmp/lldpd-{{ LLDPD_VERSION }}.tar.gz
 state: absent
-  name: Create lldpd.conf
 file:
 path: /etc/lldpd.conf
 state: touch
-  name: Configure lldpd.conf
 blockinfile:
 path: /etc/lldpd.conf
 block: |
 # Reference from https://vincentbernat.github.io/lldpd/usage.html
 configure system chassisid <chassisid>
 configure system hostname <hostname>
 configure system description <description>
 configure system platform <platform>

 configure system interface pattern eth0,eth1
 configure system interface permanent eth0,eth1

 # rx-and-tx: receive and transmit LLDP frames
 # tx-only:
 # rx-only:
 # disabled:
 configure ports eth0,eth1 lldp status tx-only

 # TTL is tx-interval * tx-hold, i.e. 120 seconds
 configure lldp tx-interval <number, default is 30 seconds>
 configure lldp tx-hold <number, default is 4>
-  name: Enable lldpd service
 systemd:
 name: lldpd
 enabled: true
 masked: false
-  name: Start lldpd service
 systemd:
 name: lldpd
 state: started

run

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ansible-playbook site.yml
# or only run role: lldp
ansible-playbook site.yml -t lldp

ansible install software from source

Thu, 30 Apr 2020 09:55:47 +0000

install lldpd from source by ansible

show the content

1

cat lldpd.yml

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---
-  hosts: localhost
 name: lldpd installation
 vars:
 lldpd_version: 1.0.22
 tasks:
 -  name: Retrieve lldpd source code
 get_url:
 url: https://github.com/lldpd/lldpd/releases/download/{{ lldpd_version }}/lldpd-{{ lldpd_version }}.tar.gz
 dest: /tmp/lldpd-{{ lldpd_version }}.tar.gz
 -  name: Extract archive
 unarchive:
 # if configured like as the following, 'Retrieve lldpd source code' task can be removed
 # src: https://github.com/lldpd/lldpd/releases/download/{{ lldpd_version }}/lldpd-{{ lldpd_version }}.tar.gz
 src: /tmp/lldpd-{{ lldpd_version }}.tar.gz
 dest: /tmp
 -  name: Configure install
 command: ./configure
 args:
 chdir: /tmp/lldpd-{{ lldpd_version }}
 creates: /tmp/lldpd-{{ lldpd_version }}/configure.status.log
 -  name: Build lldpd
 command: make
 args:
 chdir: /tmp/lldpd-{{ lldpd_version }}
 creates: /tmp/lldpd-{{ lldpd_version }}/make.status.log
 -  name: Install lldpd
 become: true
 command: make install
 args:
 chdir: /tmp/lldpd-{{ lldpd_version }}
 creates: /tmp/lldpd-{{ lldpd_version }}/make_install.status.log
 -  name: Create chroot for lldpd
 file:
 path: /usr/local/var/run/lldpd
 state: directory
 -  name: Create _lldpd group
 group:
 name: _lldpd
 state: present
 -  name: Create _lldpd user
 user:
 name: _lldpd
 group: _lldpd
 comment: lldpd user
 -  name: Remove build directory
 file:
 path: /tmp/lldpd-{{ lldpd_version }}
 state: absent
 -  name: Remove archive
 file:
 path: /tmp/lldpd-{{ lldpd_version }}.tar.gz
 state: absent
 -  name: Enable lldpd service
 systemd:
 name: lldpd
 enabled: true
 masked: false
 -  name: Start lldpd service
 systemd:
 name: lldpd
 state: started

run

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ansible-playbook lldpd.yml

Let's understand what's lldp.

Sat, 18 Apr 2020 21:08:20 +0000

LLDP

Overview

目前，网络设备的种类日益繁多且各自的配置错综复杂，为了使不同厂商的设备能够在网络中相互发现并交互各自的系统及配置信息，需要有一个标准的信息交流平台。

LLDP（Link Layer Discovery Protocol，链路层发现协议）就是在这样的背景下产生的，它提供了一种标准的链路层发现方式，可以将本端设备的主要能力、**管理地址 **、设备标识、接口标识等信息组织成不同的TLV（Type/Length/Value，类型/长度/值），并封装在LLDPDU（LLDP Data Unit，链路层发现协议数据单元 ）中发布给与自己直连的邻居，邻居收到这些信息后将其以标准MIB（Management Information Base，管理信息库）的形式保存起来，以供网络管理系统查询及判断链路的通信状况。

类似的还有Cisco Discovery Protocol, Foundry Discovery Protocol, Nortel Discovery Protocol, etc.

Frame Structure

LLDP的以太帧通常有DST MAC, SRC MAC, EtherType(0x88cc). 以及LLDPDU和FCS组成.

Ethernet Frame structure:

Preamble	Destination MAC	Source MAC	Ethertype	LLDPDU	Frame check sequence
	01:80:c2:00:00:0e, or 01:80:c2:00:00:03, or 01:80:c2:00:00:00	Station’s address	0x88CC

LLDPDU:

Chassis ID TLV	Port ID TLV	Time to live TLV	Optional TLV(s)	End of LLDPDU TLV
Type=1	Type=2	Type=3	Optional TLV	…

TLV structures:

Type	Length	Value
7 bits	9 bits	0-511 octets

TLV type values:

TLV type	TLV name	Usage in LLDPDU
0	End of LLDPDU	Mandatory
1	Chassis ID	Mandatory
2	Port ID	Mandatory
3	Time To Live	Mandatory
4	Port description	Optional
5	System name	Optional
6	System description	Optional
7	System capabilities	Optional
8	Management address	Optional
9–126	Reserved	-
127	Custom TLVs	Optional

Custom TLVs are supported via a TLV type 127. The value of a custom TLV starts with a 24-bit organizationally unique identifier and a 1 byte organizationally specific subtype followed by data. The basic format for an organizationally specific TLV is shown below:

Type	Length	Organizationally unique identifier (OUI)	Organizationally defined subtype	Organizationally defined information string
7 bits—127	9 bits	24 bits	8 bits	0-507 octets

According to IEEE Std 802.1AB, §9.6.1.3, “The Organizationally Unique Identifier shall contain the organization’s OUI as defined in IEEE Std 802-2001.” Each organization is responsible for managing their subtypes.

Work Mechanism

LLDP工作模式

TxRx: 既发送也接收LLDP报文
Tx: 只发送LLDP报文
Rx: 只接收LLDP报文
Disable: 既不发送也不接收LLDP报文

当端口的LLDP工作模式发生变化时，端口将对协议状态机进行初始化操作。为了避免端口工作模式频繁改变而导致端口不断执行初始化操作，可配置端口初始化延迟时间，当端口工作模式改变时延迟一段时间再执行初始化操作。

LLDP发送机制

当端口工作在TxRx或Tx模式时，设备会周期性地向邻居设备发送LLDP报文。如果设备的本地配置发生变化则立即发送LLDP报文，以将本地信息的变化情况尽快通知给邻居设备。但为了防止本地信息的频繁变化而引起LLDP报文的大量发送，每发送一个LLDP报文后都需延迟一段时间后再继续发送下一个报文。

当设备的工作模式由Disable/Rx切换为TxRx/Tx，或者发现了新的邻居设备（即收到一个新的LLDP报文且本地尚未保存发送该报文设备的信息）时，该设备将自动启用快速发送机制，即将LLDP报文的发送周期缩短为1秒，并连续发送指定数量的LLDP报文后再恢复为正常的发送周期。

LLDP接收机制

当端口工作在TxRx或Rx模式时，设备会对收到的LLDP报文及其携带的TLV进行有效性检查，通过检查后再将邻居信息保存到本地，并根据TTL（Time To Live，生存时间） TLV中TTL的值来设置邻居信息在本地设备上的老化时间，若该值为零，则立刻老化该邻居信息。

H3C LLDP Information

LLDP wiki

Lldp on Aurora

Run a specified role in ansible

install lldpd by ansible roles

ansible layout

show the content

site.yml

defaults/main.yml

tasks/main.yml

tasks/enable_lldp.yml

run

相关文章

ansible install software from source

install lldpd from source by ansible

show the content

run

相关文章

Let's understand what's lldp.

LLDP

Overview

Frame Structure

Work Mechanism

LLDP工作模式

LLDP发送机制

LLDP接收机制