To Choke PAGE 8 OF 15 Product service agreements are another important aspect of the single-vendor network.
Many vendors offer global access to all their support upgrades for one yearly fee.
This lets you upgrade code across the enterprise without paying multiple support fees to multiple vendors. For example, Enterasys offers all contract-support customers free access to switch code upgrades. Cisco's yearly maintenance fees gain you complete access to all downloadable software upgrades for Cisco equipment, though licensing arrangements vary. Extreme, Foundry and 3Com have similar programs in place. Likewise, with a single-vendor solution, upgrading does not require interoperability tests with each code upgrade.