雲端運算與資料中心 Cisco Data Center Interconnect 的 LAN Extension 舒念先 傳統 古典的網路設計經驗 總是將 Layer 2 網路隔離和縮小到最小的範圍 以核心層 聚合層 和存取層的三個階層架構 Layer 2 被限制到存取層 依靠 Layer 3 提供的路由 達到相互連接 隨著企業永續經營 伺服器的叢集化和虛擬化 負載平衡和災難復原等的需求 使得資料中心持 續的擴張 複雜程度增加 造成應用程式運作的範圍 不在侷限於單一資料中心的邊界 伺服器之間的溝通 高可用度的叢集化 網路和安全 都需要參與的設備具有 Layer 2 的直接連 接 在許多的實際案例 Layer 2 的功能需要延伸 超越單一資料中心的邊界 尤其是單一的框 架超越原先的地理邊界 延伸到多個遠距離的資料中心 服務供應商提供無所不在的高頻寬連接 方法 使得多個資料中心的相互連結 變得容易實現和價格低廉 一 資料中心相互連接的概論 為了能順利地部署應用程式和提供維運的彈性 兩 料中心相互連接時 需要三個類型的連接 分別是 個資料中心之間存在不同層次的連接 圖一列出資 LAN 延伸 Layer 3 延伸和 SAN 延伸 IP Routed Service L3 Primary Data Center L3 L2 VSS/vPC or MPLS or MPLSoGRE Backup Data Center L2 L2 L2 FC FC DWDM/CWDM FC FC 圖一 資料中心的相互連接 - 14 -
Cloud LAN Layer 2 Layer 3 IP Layer 2 Layer 2 Layer 2 Layer 3 Layer 3 VPN (1) ( / ) QoS LAN compute SAN compute IP Fiber Channel LAN Layer 3 SAN VLAN VLAN client VLAN (session) ( compute ) (sites) (consolidate) LAN LAN (2) L3 1. LAN Layer 2 heartbeat Layer 3 Layer 2 Layer 2 Layer 2 IP
MPLS IP Core Virtualization Applications IP Routing and IP Service Considerations Storage Extensions LAN Extensions SAN-A SAN-A DWDM/CWDM SAN-B SAN-B Server Cabinet Pair 1 Server Cabinet Pair N SAN-B Server Cabinet Pair 1 Server Cabinet Pair N Public LAN VIP Cluster Cluster A Node 1 Private LAN Heartbeat Cluster B Node 2-16 -
Cloud (3) West Coast Location Load Balance East Coast Location Server Server Server Load Balance Data Center B Server Server Server Company HQ Data Center A Ethernet PC Switch PC PC Server User Site Layer 2 IP 2. LAN IP Layer 3 Layer 2 Layer 3 Layer 2 Layer 3 LAN ( ) Layer 2 Layer 3 Layer 2 VLAN Layer 2 Layer 2
Layer 3 LAN Layer 3 Layer 3 LAN LAN STP BPDU floods MAC ARP ARP flood storm STP STP ARP MAC IP (1) LAN STP LAN Layer 2 STP LAN STP STP topology STP BPDU (flooded) Layer 2 STP topology BPDU LAN STP STP LAN LAN VLAN VLAN VLAN LAN LAN (2) Cisco LAN Cisco LAN Categories: Ethernet vpc VSS (MCECs) DWDM Cisco FabricPath vpc VSS FabricPath LAN MPLS MPLS Layer 3 Layer 2 MPLS MPLS EoMPLS Layer 2 VPLS Layer 2 MPLS IP GRE GRE EoMPLS - 18 -
Cloud VPLS Layer 2 OTV Nexus 7000 EoMPLSoGRE VPLSoGRE Ethernet IP OTV Layer 2 Layer 3 IP label Layer 2 1. IP OTV Layer 2 overlay Layer 2 Layer Nexus 2 Layer 2 Layer 2 7000 Nexus 7000 Layer 2 IP DC1 100 KM DC2 MS Cluster 2-Site Topology Core Agg Acc Acc Core Agg
Nexus 7000 (MCECs) vpc vpc (standby) 2. 100 DC1 DC2 Acc Acc Acc Agg Agg Agg Core Core Core DC1 DC3 MS Cluster MS Cluster 3-Site Topology - 20 -
Cloud MPLS 1. EoMPLS EoMPLS EoMPLS VPLS MPLS MPLS Layer 3 Core Intranet Active PW MPLS Core Active PW = Port-based EoMPLS Server Farm Server Farm EoMPLS Port Mode Deployment EoMPLS EoMPLS L3 EoMPLS GRE GRE EoMPLS VPLS EoPMLS MPLS EoMPLS VLAN session VLAN MPLS 2000 Core Agg Access Agg Core Agg Core Access
2. VPLS EoPMLS VPLS VPLS Layer 3 Core Intranet Layer 3 Core Intranet DC Core Agg Access Active PW MPLS Core Active PW Agg DC Core Access Server Farm Server Farm Layer 3 Core Intranet Server Farm DC Core Agg Access VPLS Deployment - 22 -
Cloud EoMPLS IP VPLS MPLS MPLS L1 L2 VPLS L3 L3 GRE GRE MPLS OTV VPLS virtual switch instances (VSI) IP OTV MAC MAC EoMPLS (fully IP meshed) (bridge) L2 1. OTV OTV MAC VSI Virtual OTV update Forwarding Instance (VFI) OTV OTV VLAN VFI update OTV update MAC VPLS MAC MAC VLAN 300 IP QinQ Hierachical VPLS (H-VPLS) 4 VLAN MAC IF 1 100 MAC A IP A 3 New MACs are Iearned on VLAN 100 OTV update is replicated 100 MAC B IP A by the core 100 MAC C IP A Vlan 100 MAC A 3 Vlan 100 MAC B Vlan 100 MAC C 2 East IP A VLAN MAC IF 4 West 3 100 MAC A IP A 100 MAC B IP A 100 MAC C IP A South OTV OTV Update IP C OTV Update OTV Update IP B
2. OTV OTV MAC MAC MAC IP OTV IP OTV OTV IP MAC OTV 1 Layer 2 Lookup MAC TABLE VLAN MAC IF 100 MAC 1 Eth 2 100 MAC 2 Eth 1 100 MAC 3 IP B 100 MAC 4 IP B IP A OTV 2 Encap 3 Transport Infrastructure Decap 4 MAC TABLE VLAN MAC IF IP B 100 MAC 1 IP A OTV100 MAC 2 IP A 100 MAC 3 Eth 3 100 MAC 4 Eth 4 5 Layer 2 Lookup MAC1 West Site East Site MAC 1 MAC 3 MAC3 OTV OTV OTV IP IP OTV OTV IP overlay OTV OTV OTV (multicast) OTV OTV (multihome) (loop prevention) (loadbalance) (multipathing) OTV OTV OTV (flooding) MAC MAC MAC OTV Address Resolution Protocol(ARP) (BPDU) OTV - 24 -
Cloud OTV Nexus 7000 vpc 100 OTV VLAN OTV ASR 9000 EoMPLS OTV tunnel OTV VPLS / MAC / OTV VLAN Nexus 7000 vpc Catalyst 6500 VSS EoMPLS VPLS VLAN VLAN Layer 2 ( ) 1. Cisco http://www.cisco.com