To scale the performance of WAAS / WAE and to provide high reliability, Cisco has a new feature called ITD.
Please see ITD (Intelligent Traffic Director) White Paper.
Also, recent blog : ITD: Load Balancing, Traffic Steering & Clustering using Nexus 5k/6k/7k
ITD Provides CAPEX and OPEX Savings for Customers
ITD (Intelligent Traffic Director) is a hardware based multi-Tbps Layer 4 load-balancing, traffic steering and clustering solution on Nexus 5K/6K/7K series of switches. It supports IP-stickiness, resiliency, NAT, (EFT), VIP, health monitoring, sophisticated failure handling policies, N+M redundancy, IPv4, IPv6, VRF, weighted load-balancing, bi-directional flow-coherency, and IPSLA probes including DNS.
ITD is much superior than legacy solutions like PBR, WCCP, ECMP, port-channel, layer-4 load-balancer appliances.
For example, ITD comparison with WCCP:
Feature/Benefit | N7k WCCP | N7k ITD |
Appliance is unaware of the protocol | No | Yes |
Protocol support | IPv4 | IPv4, IPv6 |
Number of TCAM entries (say, 100 SVI, 8 nodes, 20 ACEs) | Very High 16000 | Very low 160 |
Weighted load-balancing | No | Yes |
User can specify which bits to use for load-balancing | No | Yes |
Number of nodes | 32 | 256 |
Support for IPSLA probes | No | Yes |
Support for Virtual IP | No | Yes |
Support for L4-port load-balancing | No | Yes |
Capability to choose src or dest IP for load-balancing | No | Yes |
Customer support needs to look at switch only, or both the switch and appliance | Both | Switch only |
Sup CPU Overhead | High | None |
DCNM Support | No | Yes |
Email Query or feedback:ask-itd@external.cisco.com
