This Tech Tip explains the difference between multicast and unicast paging when using IP phones on the NEC SL2100, and highlights key setup considerations for each method.
Quick Tip
NEC SL2100 IP phones can receive pages via multicast or unicast packets:
- Unicast paging sends a separate stream to each receiving phone, using one DSP resource per terminal.
- Multicast paging sends a single stream shared by all phones in the group, using only one DSP resource total.
Multicast Paging
- Pros: Efficient. Only one DSP resource is used regardless of how many phones are paged.
- Cons: Cannot traverse subnets. All IP phones must reside on the same subnet as the SL2100 for multicast paging to work.
Unicast Paging
- Pros: Works across subnets, making it a flexible solution in more complex networks.
- Cons: Requires one DSP resource per receiving terminal, meaning the more phones in the paging group, the more DSP licenses are consumed.
⚠️ Important:
When using unicast, a DSP resource must be specifically configured for “Unicast Paging” on each IP phone that will receive page announcements. Without this setup, some or all phones may fail to receive the page.