This table lists the administrative distance default values of the protocols that Cisco supports:
Connected interface - 0
Static route - 1
Enhanced Interior Gateway Routing Protocol (EIGRP) summary route - 5
External Border Gateway Protocol (BGP) - 20
Internal EIGRP - 90
IGRP - 100
OSPF - 110
Intermediate System-to-Intermediate System (IS-IS) - 115
Routing Information Protocol (RIP) - 120
Exterior Gateway Protocol (EGP) - 140
On Demand Routing (ODR) - 160
External EIGRP - 170
Internal BGP - 200
Unknown* - 255
SIP Response Messages
SIP response messages are very similar to HTTP server response messages:
1xx Response - Information responses
2xx Response - Successful responses
3xx Response - Redirection responses
4xx Response - Request failure responses
5xx Response - Server failure responses
6xx Response - Global responses
1xx Response - Information responses
2xx Response - Successful responses
3xx Response - Redirection responses
4xx Response - Request failure responses
5xx Response - Server failure responses
6xx Response - Global responses
Cisco Queuing Techniques
Some basic queuing techniques available on cisco devices:
1. FIFO - this is the simplest algorithm; basically "First-In, First-Out"
2. PQ - Priority Queuing allows for the prioritization of traffic but can cause queue starvation because the top priority queue is always serviced first.
3. RR - Round-robin uses multiple queues to provide equal access to all queues but offers no prioritization.
4. WRR - Weighted-round-robin is a round-robin queue that allows for priority queues. however, but some implementations don't provide the correct bandwidth allocation because of the way bytes are counted. In cisco terms, CQ (custom queuing) is an implementation of WRR, allowing for up to 16 queues for traffic classification
5. DRR - Deficit round robin solves the problem of WRR by keeping a "deficit" county that subtracts during the following cycle any extra bytes received during the previous cycle. This is only available on the cisco 12000 series routers.
1. FIFO - this is the simplest algorithm; basically "First-In, First-Out"
2. PQ - Priority Queuing allows for the prioritization of traffic but can cause queue starvation because the top priority queue is always serviced first.
3. RR - Round-robin uses multiple queues to provide equal access to all queues but offers no prioritization.
4. WRR - Weighted-round-robin is a round-robin queue that allows for priority queues. however, but some implementations don't provide the correct bandwidth allocation because of the way bytes are counted. In cisco terms, CQ (custom queuing) is an implementation of WRR, allowing for up to 16 queues for traffic classification
5. DRR - Deficit round robin solves the problem of WRR by keeping a "deficit" county that subtracts during the following cycle any extra bytes received during the previous cycle. This is only available on the cisco 12000 series routers.
Types of QoS Models
Three different models exist for implementing quality of service (QoS) on a network:
1. Best-Effort model
2. Integrated Services (IntServ) model
3. Differentiated Services (DiffServ) model
If QoS policies are not implemented, traffic is forwarded using the Best-Effort model.
Biometric Effectiveness
From a security standpoint, here is the order of effectiveness for biometric techniques (most effective listed first):
1. Iris Scan
2. Retina Scan
3. Fingerprint
4. Hand Geometry
5. Voice Pattern
6. Keystroke Pattern
7. Signature
1. Iris Scan
2. Retina Scan
3. Fingerprint
4. Hand Geometry
5. Voice Pattern
6. Keystroke Pattern
7. Signature
Bell-Lapadula vs. Biba, Key Elements
Here are some tips for remembering details about the Bell-Lapadula and Biba security models. The B-L model is used to provide confidentiality, whereas the Biba model is used to provide integrity. When you see the word "simple", it applies to reading. If the rules uses * or "star", the rule is talking about writing.
In summary:
In summary:
- Bell-Lapadula - CONFIDENTIALITY
- Biba - INTEGRITY
- "simple" = reading
- * or "star" = writing
Biba Security Model Main Rules
1. * - Integrity Axiom - A subject cannot write data to an object at a higher integrity level. This is known as "No write up".
2. Simple Integrity Axiom - A subject cannot read data from a lower integrity level. This is known as "No read down".
2. Simple Integrity Axiom - A subject cannot read data from a lower integrity level. This is known as "No read down".
Bell-LaPadula Security Model Main Rules
1. Simple Security Rule - A subject cannot read data within an object that resides at a higher security level. This is known as "No read up".
2. * - Property Rule - A subject cannot write to an object at a lower security level. This is known as "No write down".
3. Strong Star Property Rule - For a subject to be able to read and write to an object, the subject's clearance and the object's classification must be equal.
2. * - Property Rule - A subject cannot write to an object at a lower security level. This is known as "No write down".
3. Strong Star Property Rule - For a subject to be able to read and write to an object, the subject's clearance and the object's classification must be equal.
Six Major VoIP Protocols
H.323 - ITU standard protocol for interactive conferencing
MGCP (Media Gateway Control Protocol) - a method of PSTN gateway control or thin device control
Megaco/H.248 - joint IETF/ITU standard protocol that provides full call control intelligence
SIP (Session Initiation Protocol) - a protocol that specifies commands and responses to set up and tear down calls (end-to-end call signaling); text based
RTP (Real-time Transport Protocol) - an IETF media streaming protocol
RTCP (Read-time Transport Control Protocol) - provies out-of-band control information for an RTP flow
MGCP (Media Gateway Control Protocol) - a method of PSTN gateway control or thin device control
Megaco/H.248 - joint IETF/ITU standard protocol that provides full call control intelligence
SIP (Session Initiation Protocol) - a protocol that specifies commands and responses to set up and tear down calls (end-to-end call signaling); text based
RTP (Real-time Transport Protocol) - an IETF media streaming protocol
RTCP (Read-time Transport Control Protocol) - provies out-of-band control information for an RTP flow
7 Layers of OSI Model
There are 7 layers of the OSI Model. I remember them using the phrase "All People Seem To Need Data Processing". There are others. Freel free to comment on them. Here they are:
Application
Presentation
Session
Transport
Network
Data-Link
Physical
Application
Presentation
Session
Transport
Network
Data-Link
Physical
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