Junos Enterprise Routing, 2nd Edition

Appendix A. Junos Layer 3 Services

Service is a broad term that includes Layer 2 as well as Layer 3 functions. In Chapter 9, we looked at the Layer 2 services found in Junos. Layer 3 services have undergone a dramatic change since the first edition of this book. Layer 3 services—which include NAT, IDP, VPNs, and stateful policies—are now configured as part of the security stanza described in Chapter 12 of this book. The legacy Layer 3 services (prior to Junos 9.4) are covered here for completeness. Note that as of this writing, the Juniper Networks Certified Internet Expert (JNCIE-ER) examination is based on the legacy services, and so readers interested in passing the JNCIE-ER examination will need to be familiar with ASP-based service definitions described here.

As stated previously for Layer 2 services and repeated here for clarity, for the M-series routers, enabling these services will require an additional piece of hardware: a Physical Interface Card (PIC) for packet processing. A J-series or an MX series router supports most of the Layer 3 features in software, so no additional hardware is necessary.