Data Center LAN Migration Guide - Juniper Networks

Data Center LAN Migration Guide
The scenario for transitioning the core data center network in a design upgrade triggered by a consolidation project
should encompass the following kinds of tasks, suited to each organization’s case:
• Ensure that the power, cooling, airflow, physical rack space, and cabling required for any new equipment has
been designed, ordered, and installed (however your organization breaks down these responsibilities between
departments, suppliers, and integrators).
• Size the new/upgraded switching platforms using your organization’s policy for additional performance and capacity
headroom for future growth.
• Design should include a pair of switches that can eventually serve as the new collapsed core/aggregation layer. Initial
design can be tuned to the exact role the switches will perform. For example, if they will be focused on pure core
functions in the initial phase, they can be focused on capacity/functionality required for that role (e.g., IGP policies
and area design appropriate to a core data center switch). If they will be focused on pure aggregation functions
initially, design can focus on L2 and L3 interface behaviors appropriate to that role. Or, if they will be performing a
blended core/aggregation role (as would be appropriate in many two-tier data center networks), a mix of L2 and L3
functions can be designed to fit the network’s requirements.
• If the new switches are aggregating existing access layer switches, industry standard protocols (such as 802.1D,
802.1Q, 802.1s, 802.3ad, etc.) should be used to ensure interoperability.
• Configuration checklist should include:
- IGP and EGP requirements such as area border roles, routing metrics and policies, and possible route
redistributions
- L2/L3 domain demarcations
› VLAN to VRF mapping
› Virtualized service support requirements (VPN/VRF)
› Default gateway/root bridge mapping
› Hot Standby Routing Protocol (HSRP) to Virtual Router Redundancy Protocol (VRRP) mappings
- Uplink specifications
› Density
› Speeds (number of GbE and 10GbE links)
› Link aggregations
› Oversubscription ratios
- Scaling requirements for MAC addresses
- Firewall filters (from IOS ACL mapping)
- QoS policies
- Multicast topology and performance
- Audit/compliance requirements should be clarified and any logging or statistics collection functions designed in.
- IOS configurations should be mapped to Junos OS as outlined in the section on IOS to Junos OS translation tools.
• As noted earlier, a PoC lab could be set up to test feature consistency and implementation in the new Juniper
infrastructure. Testing could include:
- Interface connections
- Trunking and VLAN mapping
- STP interoperability with any existing switches
- QoS policy (classification marking; rate limiting)
- Multicast
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