建立数据中心没有单一的方法。同样,没有单一的方法来管理数据中心结构。Cisco、第三方和开源社区提供了许多不同的工具,可用于监视、管理、自动化和排除数据中心结构的故障。
Cisco Data Center Network Manager(DCNM)是Cisco®统一结构的管理系统。它使您能够配置、监视和排除数据中心网络基础架构的故障。Cisco DCNM可以以四种模式安装:
Cisco DCNM 11.2版支持Cisco Network Insights应用程序;这些应用程序由可添加到数据中心网络管理器(DCNM)的监视实用程序组成。支持两个Cisco Network Insights应用程序:
本文档介绍了Cisco的几种spine和leaf架构设计,包括编写本文档时每个架构最重要的技术组件和设计考虑事项。
Cisco FabricPath spine and leaf网络是Cisco的专有网络。它简单、灵活、稳定,具有良好的可扩展性和快速收敛性,支持第二层多条并行路径。但是FabricPath网络是一种基于洪水和学习的第二层技术。其控制平面协议为FabricPath is-is,用于确定FabricPath交换机ID可达性信息。FabricPath交换机依靠初始数据平面流量洪泛来学习终端主机可达性信息。随着广播域中主机数量的增加,泛洪数据包的负面影响变得更加明显。第三层路由功能位于第二层网络之上。常见的第3层设计使用集中路由:即第3层路由功能集中在特定交换机(脊椎交换机或边界叶交换机)上。FabricPath网络支持多达四个用于内部VLAN路由的选播网关。
Cisco VXLAN flood and learn spine and leaf网络符合IETF VXLAN标准(RFC 7348)。它通过第3层IP底层网络传输第2层帧。但它仍然是一种基于洪水和学习的第二层技术。随着广播域中主机数量的增加,它将面临与FabricPath spine和leaf网络相同的泛洪挑战。第三层路由功能位于第二层网络之上。常见的第3层设计使用集中路由:即第3层路由功能集中在特定交换机(脊椎交换机或边界叶交换机)上。VXLAN flood and learn spine和leaf网络最多支持两个活动网关和vPC,用于内部VXLAN路由。
Cisco VXLAN MP-BGP EVPN spine and leaf架构使用MP-BGP EVPN作为VXLAN的控制平面。它符合IETF VXLAN标准RFC 7348和RFC8365(先前起草的IETF-bess-evpn覆盖)。它为VXLAN覆盖网络中的第2层和第3层转发提供控制平面和数据平面分离以及统一的控制平面。第3层内部路由通信量通过每个ToR交换机上的分布式选播网关以横向扩展的方式直接路由。VXLAN MP-BGP EVPN spine and leaf架构具有以下主要优点:
Cisco VXLAN MP-BGP EVPN spine and leaf架构是Cisco的最新创新之一。它旨在简化、优化和自动化现代多租户数据中心结构环境。
表5比较了本文中讨论的四种Cisco spine和leaf架构:FabricPath、VXLAN flood和learn、VXLAN MP-BGP EVPN和MSDC Layer 3网络。请仔细阅读此表和本文档的每个部分,并阅读参考文档以获取更多信息,帮助您选择最适合您的数据中心环境的技术。
表5. Cisco脊椎和叶子第2层和第3层结构的比较
注:自2019年7月起更新
Cisco Spine-and-Leaf Layer 2 and Layer 3 Fabric | Cisco FabricPath | Cisco VXLAN Flood and Learn | Cisco VXLAN MP-BGP EVPN | Cisco MSDC Layer 3 |
---|---|---|---|---|
Transport medium requirement | Layer 1 | Layer 3 | Layer 3 | Layer 3 |
Encapsulation | FabricPath (MAC-in-MAC frame encapsulation) | VXLAN (MAC-in-IP packet encapsulation) | VXLAN (MAC-in-IP packet encapsulation) | – |
Unique node identifier | FabricPath switch ID | VTEP | VTEP | Layer 3 IP address or loopback address |
End-host detection | Flood and learn | Flood and learn | Localized flood and learn with ARP suppression | None (localized IP subnet) |
Silent host discovery | Yes | Yes | Yes | No |
End-host reachability and distribution | Flood and learn plus conversational learning | Flood and learn | MP-BGP EVPN | Unicast routing protocol (eBGP) |
Broadcast and unknown unicast traffic | Flood by FabricPath IS-IS multidestination tree | Forwarded by underlay PIM or ingress replication(Note: Ingress-replication is supported only on Cisco Nexus 9000 Series Switches.) | Forwarded by underlay PIM oringress replication(Note: Ingress replication is supported only on Cisco Nexus 9000 Series Switches.) | Stops at leaf ToR switch |
Underlay control plane | FabricPath IS-IS | Any unicast routing protocol (static, OSPF, IS-IS, eBGP, etc.) | Any unicast routing protocol (static, OSPF, IS-IS, eBGP, etc.) | Unicast routing protocol (eBGP) |
Overlay control plane | – | – | MP-BGP EVPN | – |
Layer 3 gateway | ● Internal and external routing at border spine● Internal and external routing at border leaf● Up to 4 FabricPath anycast gateways supported | ● Internal and external routing at spine VTEP● Internal and external routing at border leaf VTEP● Up to 2 active-active gateways with vPC supported | ● Distributed anycast gateway on leaf ToR switch for inter-VXLAN routing● Border leaf switch for external routing(Note: The spine switch only needs to run BGP-EVPN control plane and IP routing.)● Border spine switch for external routing(Note: The spine switch needs to support VXLAN routing on hardware.) | ● Leaf ToR switch for internal routing● Border leaf switch for external routing |
Layer 2 VXLAN gateway | – | Leaf ToR switch | Leaf ToR switch | – |
Multicast traffic | Supports:● Layer 2 multicast traffic (forwarded by multidestination tree)● Layer 3 IP multicast traffic (forwarded by Layer 3 PIM) | Supports:● Layer 2 multicast traffic (forwarded by underlay PIM)● Layer 3 IP multicast traffic (forwarded by Layer 3 PIM) | Supports:● Layer 2 multicast traffic (forwarded by underlay PIM or ingress replication(Note: Ingress-replication is supported only on Cisco Nexus 9000 Series Switches.)● Layer 3 IP multicast traffic (forwarded by Layer 3 PIM-based multicast routing on external router or Tenant Routed Multicast (TRM)).(Note: TRM is supported on Cisco Nexus 9000 Cloud Scale Series Switches) | Supports:● Layer 3 IP multicast traffic |
Multi-tenancy | ● Layer 2 multitenancy with VN-segment● Layer 3 multitenancy with VRF-lite | ● Layer 2 multitenancy with VNI● Layer 3 multitenancy with VRF-lite | ● Support for both Layer 2 multitenancy and Layer 3 multitenancy | No |
Standard reference | TRILL-based (Cisco proprietary) | RFC 7348 | RFC 7348 and RFC8365 (previously draft-ietf-bess-evpn-overlay) | Routing protocol |
Supported hardware | ● Cisco Nexus 7000 Series Switches including the Cisco Nexus 7700 platform switches● Cisco Nexus 5500 and 5600 platform switches● Cisco Nexus 6000 Series Switches | ● Cisco Nexus 7000 Series Switches including the Cisco Nexus 7700 platform switches● Cisco Nexus 9000 Series Switches | ● Cisco Nexus 7000 Series Switches including the Cisco Nexus 7700 platform switches● Cisco Nexus 9000 Series Switches | ● Cisco Nexus 7000 Series Switches including the Cisco Nexus 7700 platform switches● Cisco Nexus 3000 Series Switches● Cisco Nexus 9000 Series Switches |
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