Cisco Systems 15310-MA manual IP-over-CLNS Tunnels, Ems

Chapter 8 Management Network Connectivity

TCP/IP and OSI Networking

In addition to the primary manual area address, you can also create two additional manual area addresses. These manual area addresses can be used to:

•Split up an area—Nodes within a given area can accumulate to a point that they are difficult to manage, cause excessive traffic, or threaten to exceed the usable address space for an area. Additional manual area addresses can be assigned so that you can smoothly partition a network into separate areas without disrupting service.

•Merge areas—Use transitional area addresses to merge as many as three separate areas into a single area that shares a common area address.

•Change to a different address—You might need to change an area address for a particular group of nodes. Use multiple manual area addresses to allow incoming traffic intended for an old area address to continue being routed to associated nodes.

8.6.7IP-over-CLNS Tunnels

IP-over-CLNS tunnels are used to encapsulate IP for transport across OSI NEs. The ONS 15310-MA SDH supports two tunnel types:

•GRE—Generic Routing Encapsulation is a tunneling protocol that encapsulates one network layer for transport across another. GRE tunnels add both a CLNS header and a GRE header to the tunnel frames. GRE tunnels are supported by Cisco routers and some other vendor NEs.

•Cisco IP—The Cisco IP tunnel directly encapsulates the IP packet with no intermediate header. Cisco IP is supported by most Cisco routers.

Figure 8-18shows the protocol flow when an IP-over-CLNS tunnel is created through four NEs (A, B, C, and D). The tunnel ends are configured on NEs A and D, which support both IP and OSI. NEs B and C only support OSI, so they only route the OSI packets.

Figure 8-18 IP-over-CLNS Tunnel Flow

NE-D NE-C

SNMP HTTP

RMON FTP

Telnet

UDP	TCP
		GRE
IPv4		Tunnel	CLNP	CLNP
LLC1			LAPD	LAPD
LAN			DCC	DCC

NE-B

CLNP

LAPD

DCC

NE-A (GNE)

	GRE
CLNP	Tunnel	IPv4
LAPD		LLC1
DCC		LAN

EMS

SNMP HTTP RMON FTP Telnet

UDP TCP

IPv4

LLC1

LAN 131956

Cisco ONS 15310-MA SDH Reference Manual, Release 9.1 and Release 9.2

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