A data center has several legacy IBM mainframes that only support Systems Network Architecture
(SNA) traffic. The mainframes are located in different areas of the data center. What should the
network architect plan in this solution?
A.
how to prioritize the SNA traffic based on its DSCP in order to ensure low latency
communication
B.
how to implement SNA to IP tunneling on the HP server access layer switches
C.
how to implement Edge Virtual Bridging (EVB) to tunnel to SNA traffic securely
D.
how to isolate the mainframes in a VLAN and extend Layer 2 connectivity between them
The answer is D.
Taken from the Study Guide, Figure 12-11
SNA – IBM Mainframe – Isolate to one VLAN, for distributed data centers, ensure Layer 2 WAN services.
The previous paragraph in the guide also says: You must place all DECnet (and SNA) devices on the same VLAN.
There is no mention of DSCP, IP Tunneling, or EVB anywhere.
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D is correct
The customer’s best option is to upgrade the devices to OS versions that support
both the legacy protocol and IP. For example, HP has offered DECnet Phase V
Plus in its OpenVMS solutions for several years. This version of DECnet has a
TCP/IP stack that enables the device to communicate with the private intranet and
public Internet. At the same time, the device continues to use DECnet, appear as a
DECnet device to other DECnet devices, and run all the necessary DECnet-based
applications. IBM offers SNA over IP solutions with similar benefits.
If the customer cannot upgrade at this time, you must assess what type of support
your solution must provide. Presumably, the DECnet or SNA network is already in
place and operational, and you must simply ensure that your proposed solution fits
with these networks in the same way the customer’s previous solution did.
For example, the customer might require the data center network infrastructure to
connect islands of devices running DECnet Phase 4, which uses Ethernet to
encapsulate DECnet at Layer 3. You must place all of the DECnet devices on the
same VLAN. This creates a container for the DECnet network in which the existing
DECnet systems can continue to operate. If you need to connect DECnet islands
over WAN connections, keeping the devices on the same VLAN becomes more
complicated. Solutions for running DECnet over IP exist, but usually it is better to
upgrade to DECnet Phase V Plus.
The same considerations hold true for SNA. Note that some HP products can
select SNA traffic and automatically place it within a specific protocol-based VLAN.
If your proposed devices do not support this capability, you will simply need to
ensure that the DECnet or SNA devices are placed in the correct VLAN manually.
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