2. SONIC
有了(le) SAI, 這(zhè)讓網絡操作(zuò)系統不再關心底層怎麽與專有硬件通信，操作(zuò)系統廠(chǎng)商可以專注于網絡操作(zuò)系統的開(kāi)發，其中以 SONIC 最爲突出，他(tā)是 Microsoft/Azure 網絡操作(zuò)系統，由微軟和(hé)多家廠(chǎng)商一起開(kāi)發，并且開(kāi)源。
2.1. 什(shén)麽是SONIC?
SONiC 是一個基于 Linux 的開(kāi)源網絡操作(zuò)系統，運行在多個供應商和(hé) ASICs 的交換機上(shàng)。SONiC 提供一整套網絡功能(néng)，如 BGP 和(hé) RDMA，這(zhè)些(xiē)功能(néng)在一些(xiē)最大(dà)的雲服務提供商的數據中心經過生産驗證。它爲團隊提供了(le)創建所需網絡解決方案的靈活性，同時(shí)利用(yòng)大(dà)型生态系統和(hé)社區(qū)的集體力量。
2.2. SONIC 系統架構[13]
SONIC 系統的體系結構由各種模塊組成，這(zhè)些(xiē)模塊通過一個集中的、可伸縮的基礎設施彼此交互。這(zhè)個基礎結構依賴于 redis-database 引擎的使用(yòng): 鍵值數據庫提供獨立于語言的接口、數據持久性、複制和(hé)所有聲音(yīn)子系統之間的多進程通信的方法。
SONIC 通過依賴 redis-engine 基礎結構提供的發布者/訂閱者消息傳遞範式，應用(yòng)程序可以隻訂閱它們所需的數據視(shì)圖，并避免與其功能(néng)無關的實現(xiàn)細節。
SONIC 将每個模塊放(fàng)在獨立的docker容器中，以保持語義仿射組件之間的高(gāo)内聚性，同時(shí)減少脫節組件之間的耦合。每個組件都被編寫爲完全獨立于平台特定的細節，而這(zhè)些(xiē)細節是與低(dī)層抽象交互所必需的。
SONIC 将其主要功能(néng)組件分解爲以下(xià) docker 容器：
- Dhcp-relay
- Pmon
- Snmp
- Lldp
- Bgp
- Teamd
- Database
- Swss
- Syncd
2.3. SONIC 的功能(néng)發展
我們來(lái)看(kàn)一下(xià) SONIC 的功能(néng)發展 (來(lái)源于 SONIC 官網) [14]
| Release | Release Date | SAI version | Features Included |
| SONiC.201705 | 5/15/2017 | 0.9.4 | BGP |
| ECMP | |||
| LAG | |||
| LLDP | |||
| QoS – ECN | |||
| QoS – RDMA | |||
| Priority Flow Control | |||
| WRED | |||
| COS | |||
| SNMP | |||
| Syslog | |||
| Sysdump | |||
| NTP | |||
| COPP | |||
| DHCP Relay Agent | |||
| SONiC to SONiC upgrade | |||
| Multiple Images support | |||
| One Image | |||
| SONiC.201709 | 9/15/2017 | 0.9.4 | VLAN |
| ACL permit/deny | |||
| IPv6 | |||
| Tunnel Decap | |||
| Mirroring | |||
| Post Speed Setting | |||
| BGP Graceful restart helper | |||
| BGP MP | |||
| SONiC.201712 | 12/15/2017 | 1 | Fast Reload |
| SONiC Support SAI 1.0 | |||
| TACACS+ | |||
| LACP Fallback | |||
| MTU Setting | |||
| Vlan Trunk | |||
| Static Port breakout1 | |||
| Dynamic ACL Upgrade | |||
| SWSS Unit Test Framework | |||
| CobfigDB framework | |||
| SONiC.201803 | 3/15/2018 | 1.2 | |
| Critical Resource Monitoring | |||
| MAC Aging | |||
| IPv6 ACL | |||
| BGP/Neighbor-down fib-accelerate | |||
| PFC WD | |||
| SONiC.201807 | 7/30/2018 | 1.3 | |
| gRPC | |||
| Dtel support | |||
| SONiC Architecture and User Manual (Documentation) | |||
| Sensor transceiver monitoring | |||
| LLDP extended MIB: lldpremtable, lldplocporttable, lldpremmanaddrtable, lldplocmanaddrtable, lldplocporttable, lldpLocalSystemData | |||
| SONiC.201811 | 11/30/2018 | 1.3 | Release Note |
| Debian Kernel Upgrade to 4.9 | |||
| Warm Reboot | |||
| Incremental Config (IP, LAG, Port shut/unshut) | |||
| Asymmetric PFC | |||
| PFC Watermark | |||
| Routing Stack Graceful Restart | |||
| Basic VRF and L3 VXLAN | |||
| SONiC.201904 | 4/30/2019 | 1.4 | Release Note |
| FRR as default routing stack | |||
| Upgrade each docker to stretch version | |||
| Upgrade docker engine to 18.09 | |||
| Everflow enhancement | |||
| Egress ACL bug fix and ACL CLI enhancement | |||
| L3 RIF counter support | |||
| PMon Refactoring | |||
| BGP-EVPN support(type 5), (related HLD Fpmsyncd,Vxlanmgr,template) | |||
| Transceiver parameter tuning PR pending on CR sign off | |||
| SONiC.201910 | 10/30/2019 | 1.5 | Progress Tracking |
| ZTP – design review in progress | |||
| BFD – SW – 100ms interval from FRR | |||
| NAT | |||
| STP/PVST | |||
| Mgmt VRF | |||
| Multi-DB optimization | |||
| Test to Pytest | |||
| sFlow | |||
| Management Framework (Tentative ) | |||
| Platform Driver Development Framework | |||
| Build Improvements | |||
| Error handling enhancements | |||
| L2 functional and performance enhancements | |||
| L3 perf enhancement | |||
| BroadView BST | |||
| VRF | |||
| Configuration Validation | |||
| Dynamic Break Out | |||
| Platform APIs move to new APIs * | |||
| Sub-port support | |||
| Backlog | |||
| CLI framework | |||
| VRF (Taken) | |||
| L3 MLAG (Taken) | |||
| EVPN | |||
| RDMA CLI enhancement | |||
| Virtual path for streaming telemetry (pushed off) | |||
| Management VRF (pushed off) | |||
| Port and Vlan configuration and validation (TBD) |
3. 結束語
今天我們先聊這(zhè)些(xiē)，我們大(dà)緻了(le)解一下(xià)開(kāi)放(fàng)型網絡包含的幾個重要組件，開(kāi)源軟件的概念，開(kāi)源的網絡操作(zuò)系統的概念，開(kāi)放(fàng)的計(jì)算(suàn)硬件有何而來(lái)，軟件定義網絡的概念，但(dàn)是開(kāi)放(fàng)型網絡中還包含以下(xià)組件：
- 網絡功能(néng)虛拟化
- 雲計(jì)算(suàn)
- 自(zì)動化
- 敏捷型開(kāi)發方法和(hé)處理(lǐ)過程
SONIC 作(zuò)爲網絡操作(zuò)系統在其中扮演很(hěn)重要的角色，如果想進一步了(le)解 SONIC 子系統的各個功能(néng)以及邏輯，網絡功能(néng)虛拟化，雲計(jì)算(suàn)，網絡自(zì)動化，以及敏捷型開(kāi)發方法和(hé)處理(lǐ)過程，請(qǐng)關注我們。
參考文(wén)獻：
[1] https://en.wikipedia.org/wiki/Software-defined_networking
[2] https://en.wikipedia.org/wiki/Open_source
[3] https://en.wikipedia.org/wiki/Open-source_software
[4] https://www.opencompute.org/about
[5] https://aptira.com/what-is-open-networking/
static/file/file
[7] https://www.opencompute.org/wiki/Networking/ONIE
[8] https://www.openswitch.net/about/
[9] http://opennetlinux.org/
static/file/file
static/file/file
[12] https://www.opencompute.org/documents/switch-abstraction-interface
[13] https://github.com/Azure/SONiC/wiki/Architecture
[14] https://github.com/Azure/SONiC/wiki/Sonic-Roadmap-Planning