This will be a dynamic document to document all the scenarios where it’s not clear which is better; A higher value or a lower value?
I have noticed that as a general rule; For layer 2 technologies a lower value is preferred and for layer 3 a higher value is prefered. The purpose of this post is to keep a list so I can see if this rule holds out or is proven wrong on some occasions.
Cisco
Value
Default Value
Preferred value
HSRP Priority
100
Higher
BGP Local-preference
100
Higher
BGP Weight (Cisco)
0
Higher
BGP MED
0
Lower
Spanning-tree bridge ID
32768
Lower
Router ID auto selection
IP Address1
Higher
1The highest active configured IP on a loopback is preferred. If there are no lookbacks then the highest IP address on an active interface is chosen next.
Palo Alto
Value
Default Value
Preferred value
HA Device Priority
100
Lower2
2The palo alto documentation covers this is a very confusing manner. It states that the device with the highest device priority is chosen as the active. It goes on to say that a lower integer value means the device has a higher priority.
The following is a list of networking Mnemonics which I have either created, been told about or read about as a method of remembering various aspects of networking as part of my study. This list will be updated as time goes on:
The OSI Model
OSI Layer
Mnemonic
OSI Layer description
1
People
Physical
2
Don’t
Data-link
3
Need
Network
4
Those
Transport
5
Stupid
Session
6
Packets
Presentation
7
Anyway
Application
The OSI Model (Alternative) Please Do Not Take Sales Peoples Advice
EIGRP K Values
K Value
Mnemonic
K Value Description
K1
Big
Bandwidth
K2
Latencies
Load
K3
Don’t
Delay
K4
Really
Reliability
K5
Matter
MTU
Bear in mind that the Cisco format for entering the metric is as follows
Always remember that delay is in units of 10 micro seconds and so a value of 10 is actually equal to 100 micro seconds of delay.
OSPF LSA Types
LSA Type
Mnemonic
LSA Description
Type 1
Right
Router LSA
Type 2
Now
Network LSA
Type 3
Some
Summary LSA
Type 4
Argue
ASBR Summary LSA
Type 5
As1
ASBR External LSA
Type 6
Good
Group Membership LSA
Type 7
Network
NSSA LSA
Type 8
Engineers
External Attributes
Type 9
Look
Link Scope Opaque
Type 10
Always
Area Scope Opaque
Type 11
Aside
AS Scope Opaque
1 Think of As path to remember external
Cisco BGP Attributes (NB: Not yet completed)
BGP Metric
Mneumonic
Preference
Significance
Requirement
Weight
–
Highest
Local
–
Local Preference
–
Highest
Local AS
–
Local originated
–
Local originated
Local
–
AS Path
–
Shortest
Global
–
MED
–
Lower
Global
–
External
–
eBGP > iBGP
–
–
IGP cost
–
Lowest
–
–
eBGP Peerin
–
Oldest
–
–
Router ID
–
Lowest
–
–
BGP attributes are evaluated from the top down. Preference is which value is better than another value and significance is whether that property carries to other AS, Is local to the AS or is local to the device. Compatibility is whether something is vendor proprietarty.
