Enterprise Data Center Design

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Cisco Catalyst 6500 serie switches Cisco Data Center Technologies

Designing The Core and Aggregation Layers

Data Center Design Architectural Overview

Data Center arkitekturen er baseret på en tre lags model.

• Core laget består af høj-hastigheds OSI lag 3.
• Aggregation laget forbinder Access-Laget med enten OSI lag 2 eller OSI lag 3.
• Access Laget giver fysisk forbindelse til Serverne.

fordele ved tre-lags modellen

• Hvis det er nødvendigt at samme VLAN skal være på flere Access Switche samtidig kan Aggregation-Switchene-----

Data Center Core layer design

Data Center Core Layer Design

OSI Lag 3 design for Data center Core

Routnings Protokoller

OSPF

OSPF Routnings Protokol design for Data Center Core

EIGRP

EIGRP Routnings Protokol design for Data Center Core

Aggregation Layer

Scalering af Data Center Aggregation laget

Spanning tree design

Cisco anbefaler at benytte sig af RPVST+.

Data Center Spanning Tree design (Aggregation switche Root/HSRP)

Aktiv STP,HSRP og Service Context Alignment

Active/Standby Service Module Design

I tegningen herunder er den ene Aggregation Switch Active og den anden Standby for al trafikken fra Access laget.

• Cisco 6500 med FSWM 2.x

Aggregation switche Aktiv/Standby STP,HSRP og Service Module design, eksempel 1

Aggregation switche Aktiv/Standby STP,HSRP og Service Module design, eksempel 2

Active/Active Service Module Design

I tegningen herunder er begge Aggregation Switche Active for hver deres VLAN's.

• Cisco 6500 med FSWM 3.1

Establisheing Inbound Path Prefenrece

Route Health Injection(RHI) tillader at en Cisco CSM/ACE i en 6500 switch installerer en hoste route til den virtuelle server. /32 routen fjerner problemer med asymmetriske routing.

Anvendelse af VRF (MPLS) i Data centeret

Anvendelse af VRF'er i Data Centeret

Access Lag

Lag 2 - Looped design

I Lag to Looped Design er VLAN's termineret i Aggregation laget og Lag 2 services som NIC teaming, Clustering og Statefull Services som for eksempel Firewall, Server Load Balancing, SSL kan udføres på ISO lag 2. Lag tre Routning foregår på Aggregations laget.

Lag 2 - Looped design
Looped design Square Access	Looped design Triangle Access

Lag 2 - Loop frit design

I Lag to Loop frit design er der ikke VLAN på Aggregationslaget modsat Looped design (Se overnfor). Ved omvendt U er det dog muligt at have VLAN på Aggregationslaget. Lag to services er supporteret. Lag tre Routning foregår på Aggregations laget.

Loop fri Access topologi. - U Access	Loop fri Access topologi - Omvendt U Access
Loop free U with Layer 2 Services Modules

Sammenligning af lag to Access designs

Sammenligning af lag 2 Access Designs

Lag 3 på Access laget

Statefull Services som kræver lag to konnektivitet kan ikke udføres af Aggregationslaget hvis Lag tre Routning foregår på Access-laget.

OSI Lag 3 på Access laget

Multicast Source Support

OSI Lag 3 på Access laget Multicast Support

6500 Services Module Placement Considerations

6500 Switch Fabrics

Optimizing EtherChannel U tilization with Min-Links

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STP in the DataCenter

RSTP is the most common STP used in the data center today, and is the implementation recommended by Cisco for the enterprise data center.

• It scales to a large size (about 10,000 logical ports).
• Coupled with UDLD, loop guard, root guard, and BPDU guard, it provides a strong and stable Layer 2 design solution.
• It is a proven solution that is easy to implement and scale.

MST is not as common in the enterprise data center because of its characteristics:

• It permits large-scale STP implementations (about 30,000 logical ports). This is typically more useful for service providers and application service providers.
• It isn’t as flexible as RSTP.
• It has service module implications for firewalls in transparent mode.
• It is more commonly used with service providers and application service providers.

Limit HSRP instances: The number of VLANs is typically tied to the number of HSRP instances. Cisco recommends a maximum of 500 HSRP instances on the Catalyst 6500 series Supervisor Engine 720 with default timers.
Use MST if it meets the requirements: If you cannot support the STP scaling issues with RSTP, you can consider implementing MST.

High Availability and Failover Times

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High Availability and Cisco NSF with SSO

This convergence time and possible lost sessions can be avoided by using dual Catalyst 6500 series Supervisor Engine 720 engines and Cisco NSF with SSO on the primary aggregation switch of the data center.

Eksterne henvisninger

• Data Center design
• Cisco catalyst 6500 serie præsentation