4.0 IP Services (10%)
Maximum SYSLOG storage
8K (8192 bytes) in RAM. Logs are not stored permanently on the router. Reboot and they are gone.
NAT Pool
A pool of IP addresses to be used as inside global or outside local addresses in translations (many to many)
Class Selector (CS)
A set of 8 standard DSCP values, provides backward compatibility with IPP (DSCP replaced the older IPP standard). all values end with binary 000,
Expedited Forwarding (EF)
DSCP value for low loss/latency/jitter traffic (usually voice) Value = 46
AF (Assured Forwarding)
DSCP value that defines four traffic classes. All packets in a class have the same priority. . Within each class, there are three levels of drop precedence. - Higher drop precedence = more likely to drop the packet during congestion
Traffic Class
This IPv6 header includes this field that is used for marking traffic with Differentiated Services Code Point (DSCP) values
ntp master
command configures a device as an authoritative clock source.
ntp server
command configures a local device to synchronize its time from another NTP server. The configured server can still be the NTP server for other devices as long as it has its own primary clock source.
ntp peer
command that configures a device to synchronize its time with the configured peer, and to supply time information back to that peer.
Low Latency Queuing (LLQ)
congestion management solution was designed specifically for traffic that has specific low delay, jitter, and loss requirements. It provides preferential treatment for one "strict priority traffic queue" (voice). It then splits the rest of the link's bandwidth between the other traffic queues/types.
Inside local
The NAT private IP address that I use on my local LAN.
NTP server will sync issues
The loop back address of a NTP master must be added to any ACL the server uses. The sync process is slow and may need the device clock set closer to the server clo0ck.
Inside Global
The public IP address that the inside NAT host's IP address will be translated into for external networks.
Managed Objects (MOs)
The variables on these managed devices are called. They are organized in a tree that is called a Management Information Base (MIB). Each one has a unique identifier in the MIB tree, and these are called Object Identifiers (OIDs).
SNMP V2.c
Uses an unencrypted password called community string.
A Management Information Base (MlB)
a SNMP component that takes the form of a tree of variables that can be managed and monitored by the protocol.
SSH (Secure Shell)
a remote administration protocol that allows users to manage remote devices over the Internet. It uses encryption to secure communication between the user and the remote device.
CoS (Class of Service)
a value in the 802.1p trunking field of an ethernet header that sets the traffic priority. It only works over layer 2 trunk and voice access links. layer 3 traffic control methods are more effective. It is also known as PCP
Inform messages
alternative SNMP message process supported by SNMP Version 2 that requires acknowledgment by the NMS (considered reliable).
Default Forwarding (DF)
best effort traffic DSCP Value (0)
Shaping
Buffering and delaying packets to comply with predefined traffic profiles. To control the flow of traffic by introducing delays and ensuring it conforms to desired rates. Temporarily stores and schedules packets for transmission. Helps avoid network congestion and bursty traffic.
Nexus 1000V
Cisco virtualization offering that can be used to completely replace the functionality of the VMware vSwitch
Trap messages
Devices send these SNMP messages with no acknowledgment that the NMS received the message. (considered unreliable).
SNMP (Simple Network Management Protocol)
Internet-standard protocol used for managing and monitoring network devices, such as routers, switches, servers, and printers. allows network administrators to gather information and control network devices from a central management system.
Outside Local
It is the destination IP address that the packet was sent to for before NAT changed it to a fake internal IP.
Queuing
Managing the order in which packets are processed and transmitted based on their assigned priorities or service classes to ensure fair and predictable access to network resources during periods of congestion. Algorithms (FIFO, WFQ) prioritize and schedule. Configured with different queuing disciplines (e.g., strict priority, weighted round-robin).
Congestion Avoidance
Mechanisms that monitor congestion and take proactive measures to prevent or alleviate congestion. to maintain network stability and prevent packet loss due to congestion. Examples include TCP congestion control algorithms (e.g., TCP Reno). Helps manage network resources efficiently.
SNMP V3 features
Message integrity Authentication Encryption
Marking
Process of assigning a QoS label or Differentiated Services Code Point (DSCP) to packets to indicate their priority or treatment. To provide a way for routers and switches to prioritize traffic based on its importance. Uses DSCP values in IP headers.
Classification
Process of identifying and categorizing network traffic based on predefined criteria; source, destination, and application. To differentiate and group traffic for QoS treatment. Identifies packets based on rules/rulesets. Typically performed at the ingress of a network device.
Policing
Process of monitoring and controlling the rate of traffic to enforce predefined bandwidth limits. To enforce traffic profiles and discard or remark packets that exceed the allowed rate.
DHCP
Protocol that once it is configured on the server centrally distributes IP information to clients.
Command to Verify current time
R1#show clock.
Command to Show Logging
R1#show logging
Command to enable logging
R1#terminal monitor
Command to Verify NAT
Router1#show ip nat translation
SMTP V3
SMTP that Uses encryption
NTP stratum level
Servers with lower numbers are preferred by other devices if multiple NTP servers are available. Each hop in the hierarchy a server will add +1 to the number. NTP top level servers that reference their own time device and have lowest number.
maximum stratum value
Stratums higher than 16 are considered unreliable and ignored by IOS.
Traffic Class
The IPv6 header includes this field that is used for marking traffic with Differentiated Services Code Point (DSCP) values
Syslog messages port
User Datagram Protocol (UDP) port 512 by default.
CBWFQ (Class-Based Weighted Fair Queuing)
is a popular method of scheduling, using a weighted round-robin scheduler while guaranteeing each queue a certain percentage of the interface's bandwidth during congestion.
SNMP Object Identifier (OID)
is an identifier that is used to address the variables in the MIB tree, not the tree itself.
SNMP agent
is software on the managed device that is responsible for the communication between the managed device and the NMS. It sets and retrieves values from the SNMP MIB.
SNMP Network Management Station
is the software that sends SNMP SET and GET messages to manage and monitor network devices. It also receives TRAP and INFORM messages.
DNS-Domain Name System
is used to resolve FQDN (fully qualified domain name) to an IP address.
weighted round-robin
more data is taken from high priority queues each time the scheduler reaches that queue.
Command to make NTP act as server only
ntp master{stratum-level}:
Command make router act as both NTP client and server
ntp server{address|hostname}:
round-robin queuing
packets are cyclically sent from each queue in order.
logging trap command
sets the severity level of syslog messages. Syslog is a logging messages standard. The severity level is defined using an integer from 0 to 7.
NTP client/server mode
the device acts as both client and server. First, it acts as an NTP client, to synchronize time with a server. Once synchronized, the device can then act as an NTP server, to supply time to other NTP clients.
NTP server mode
the device acts only as an NTP server, and not as an NTP client. The device gets its time information from the internal clock on the device with the
