# Service Type

Service types define the guaranteed level of service in a [ATM](/glossary/a/atm) network. This involves such things as the timing between the source and destination, the guaranteed bandwidth and how many cells get lost in transmission.

^ Setting ^ Description ^
| UBR without PCR | Use [Unspecified Bit Rate](/glossary/u/ubr) without [Peak Cell Rate](/glossary/p/pcr). |
| UBR with PCR | Use [Unspecified Bit Rate](/glossary/u/ubr) with [Peak Cell Rate](/glossary/p/pcr). |
| CBR | Use [Constant Bit Rate](/glossary/c/cbr). |
| Non-Realtime VBR | Use Non-Real-Time [Variable Bit Rate](/glossary/v/vbr). |
| Realtime VBR | Use Real-Time [Variable Bit Rate](/glossary/v/vbr). |