Chapter 22 Advanced DHCP Server Properties

Defining Advanced Server Parameters

Table 22-1 DHCP Advanced Parameters (continued)

Advanced Parameter

Action

Description

max-dhcp-responses

set/

Controls the number of response buffers that the DHCP server

 

unset

allocates for responding to DHCP clients and performing failover

 

 

communication between DHCP partners.

 

 

In a non-failover deployment, the default setting of twice the

 

 

number of request buffers is sufficient. In a failover deployment, you

 

 

can increase this so that it is four times the number of request

 

 

buffers. In general, increasing the number of response buffers is not

 

 

harmful, while reducing it to below the previously recommended

 

 

ratios might be harmful to server responsiveness.

 

 

Some log messages that might trigger a change in this value are:

 

 

4721 DHCP ERROR "DHCP has used all xx response packets. A

 

 

request was dropped and they will continue to be dropped

 

 

if no responses are available."

 

 

5289 DHCP WARNING "DHCP has used xx of yy response

 

 

packets. Requests will be dropped if no responses are

 

 

available."

 

 

Required. The default is 1000.

 

 

 

max-ping-packets

set/

Controls the number of buffers that the server has available to

 

unset

initiate Ping requests to clients. If you enable the Ping address

 

 

before offering it option at the scope level, packet buffers are used

 

 

to send and receive ICMP messages. If you enable pinging, you

 

 

should have enough ping packets allocated to handle the peak load

 

 

of possible ping requests. The default is 500 ping packets.

 

 

 

hardware-unicast

enable/

Controls whether the DHCP server sends unicast rather than

 

disable

broadcast responses when a client indicates that it can accept a

 

 

unicast. This feature is only available on Windows NT, Windows

 

 

2000, and Solaris platforms; other operating systems broadcast

 

 

instead. The default is enabled.

 

 

defer-lease-extensions enable/

Controls whether the DHCP server extends leases that are less than

 

disable

half expired. This is a performance tuning attribute that helps

 

 

minimize the number of disk writes to the lease state database. The

 

 

default is checked or true. This means that a client renewing a lease

 

 

less than halfway through can get the remaining part of it only and

 

 

not be extended. See the “Deferring Lease Extensions” section on

 

 

page 22-6.

 

 

last-transaction-time- set/

Specifies the number of seconds that guarantees the last transaction

granularity

unset

time to be accurate. This is a performance tuning attribute whereby

 

 

the server avoids frequent disk writes to the lease state database by

 

 

ignoring duplicate client activity (such as renews) within the set

 

 

granularity. Do not set this lower than 30 seconds. For optimal

performance, set it to a value that is greater than half the lease interval. The default is 60 seconds.

Step 1 In the local cluster Web UI, click DHCP, then DHCP Server to open the Manage DHCP Serve page.

Cisco CNS Network Registrar User’s Guide

 

OL-6240-02

22-5

 

 

 

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Cisco Systems OL-6240-02 manual 22-5
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OL-6240-02 specifications

Cisco Systems OL-6240-02 is a highly regarded certification exam that delves into the realm of enterprise networking, particularly focusing on the Cisco Certified Network Professional (CCNP) Routing and Switching track. This particular exam serves as a critical test for network professionals aiming to validate their skills and knowledge in advanced routing technologies and network design.

One of the main features of OL-6240-02 is its emphasis on in-depth understanding of IP routing principles. Candidates are expected to demonstrate proficiency in configuring, maintaining, and troubleshooting complex routing protocols like OSPF (Open Shortest Path First), EIGRP (Enhanced Interior Gateway Routing Protocol), and BGP (Border Gateway Protocol). This includes comprehending routing algorithms, path selection, and the implementation of route redistribution, which are essential for optimizing network performance.

The exam also covers the characteristics of network security and infrastructure, where candidates must exhibit knowledge of implementing security protocols and best practices to safeguard network communications. This includes configuring virtual private networks (VPNs), utilizing access control lists (ACLs), and applying encryption techniques to secure data in transit.

Another crucial technology tested in OL-6240-02 is Quality of Service (QoS). Professionals must be adept at configuring QoS mechanisms to prioritize traffic, ensuring that critical applications receive the necessary bandwidth and latency requirements. This is increasingly important as businesses rely on a multitude of applications that have varying performance needs.

Cisco's emphasis on network automation and programmability is also a focal point of this certification. Candidates are expected to be familiar with using Cisco's software-defined networking (SDN) solutions and automation tools, which are essential for modern network management. This involves understanding how to leverage APIs and modeling tools to streamline network operations and enhance efficiency.

To succeed in OL-6240-02, candidates should possess a solid foundation in network fundamentals and have hands-on experience with Cisco devices. The certification not only validates expertise but also prepares professionals for real-world challenges in designing, implementing, and troubleshooting enterprise networks. Overall, OL-6240-02 is a stepping stone for network professionals seeking higher-level certifications and career advancements in the ever-evolving field of networking.
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