Transcript Week_Nine_Networkx

ITEC 275
Computer Networks – Switching, Routing, and
WANs
Week 9
Robert D’Andrea
Winter 2017
Agenda
• Learning Activities
– Network Management Processes
• Syslog
– Network Management Architectures
– Network Management Tools and Protocols
– Campus Cabling
– Ethernet
– Campus Network Design Example
Network Management Processes
• International Organization for Standardization
(ISO) defines five types of network processes
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Fault management
Configuration management
Accounting management
Performance management
Security management
Network Management Processes
• Fault management refers to detecting, isolating,
diagnosing, and correcting problems.
- Develop a workaround(s)
- Test the workaround(s)
- Document the workaround(s) in a problemtracking database
- Utilize monitoring tools to alert managers,
protocol analyzers and Wire Shark for fault
resolution
- Syslog network contains timestamp, level,
and facility. Syslog severity levels are
provided
Network Management Processes
Syslog is a standard for computer message logging.
Syslog can be used for computer system
management and security auditing as well as
generalized informational, analysis, and debugging
messages. It is supported by a wide variety of
devices (like printers and routers) and receivers
across multiple platforms. Because of this, syslog
can be used to integrate log data from many
different types of systems into a central repository.
Network
Management
Processes
Syslog is a standard for computer message logging.
/var/log>ls
anaconda.log
anaconda.program.log
anaconda.storage.log
anaconda.syslog
anaconda.xlog
anaconda.yum.log
audit
boot.log
boot.log-20151004
boot.log-20151011
boot.log-20151018
boot.log-20151025
btmp
btmp-20151001
messages-20151004
messages-20151011
messages-20151018
messages-20151025
mysqld.log
ntpstats
ppp
prelink
RPM-GPG-KEY-EPEL
RPM-GPG-KEY-EPEL-6.pub
sa
salt
secure
secure-20150809.gz
Network
Management
Processes
• Syslog is a standard for computer message logging.
/var/log>ls
client-config-overrides.txt
client_config_update.py
ConsoleKit
cron
cron-20140921.gz
cron-20140928.gz
cron-20141005.gz
cron-20141012.gz
cron-20151004
cron-20151011
cron-20151018
cron-20151025
cups
dmesg
dmesg.old
secure-20150816.gz
secure-20150823.gz
secure-20150830.gz
secure-20151004
secure-20151011
secure-20151018
secure-20151025
spooler
spooler-20151004
spooler-20151011
spooler-20151018
spooler-20151025
sssd
tallylog
up2date
Network Management Processes
• Syslog is a standard for computer message logging.
/var/log>ls
httpd
up2date-20151004
lastlog
up2date-20151011
mail
up2date-20151018
maillog
up2date-20151025
maillog-20150809.gz VMWARE-PACKAGING-GPG-DSA-KEY.pub
maillog-20150816.gz
vmware-tools-guestd
maillog-20150823.gz
wtmp
maillog-20150830.gz
wtmp-20150901
maillog-20151004
yum.log
maillog-20151011
yum.log-20120101
maillog-20151018
yum.log-20130101
maillog-20151025
yum.log-20140101
messages
yum.log-20150101
Network Management Processes
Most syslog messages are found on Unixlike operating systems under the /var/log
directory.
anaconda.log
boot.log
RPM-GPG-KEY-EPEL
ppp
mysqld.log
yum.log
cups
sssd
dmesg
httpd
spooler-20150208
cron-20140921.gz
maillog
audit
Network Management Processes
Anaconda is the installation program used by
Fedora, Red Hat Enterprise Linux.
During an installation, a target computer's hardware
is identified and configured and the appropriate file systems
for the system's architecture are created. Finally, Anaconda
allows the user to install the operating system software on
the target computer.
Anaconda can also upgrade existing installations of
earlier versions of the same distribution. After the
installation is complete, you can reboot into your installed
system and continue doing customization using the initial
setup program.
Network Management Processes
Syslog Messaging Levels
- Emergency (level 0)
- Alert (level 1)
- Critical (level 2)
- Error (level 3)
- Warning (level 4)
- Notice (level 5)
- Information (level 6)
- Debugging (level 7)
Network Management Processes
Syslog Messages
- Sent to Cisco router or switch consoles
- Sent to Network Management Station
- Sent to a remote network host where a
syslog analyzer is installed. A syslog
analyzer distributes these messages
appropriately to the network node
manager, and management.
Network Management Processes
• Configuration Management helps the network
manager maintain a list of devices and
information installed on those devices.
- Version-logging refers to keeping track of
the version of operating systems or
applications running on network
devices.
- Change management includes DHCP and
VLAN Trunk Protocol (VTP)
automatically updates switches with
VLAN information.
Network Management Processes
Network Management Processes
Dynamic Host Configuration Protocol
(DHCP) allows for manual and automatic
assignment of IP addresses (see IETF RFC 2131
& 2132). DHCP is enacted when a new machine
joins a network or an existing machine attempts to
renew its IP address. DHCP is an extension of an
older protocol known as the "bootstrap protocol"
(BOOTP) and is backwards compatible with
BOOTP. There are three methods of IP address
allocation:
Network Management Processes
Manual: An administrator manually assigns the
IP address; tedious but most secure
method.
Automatic: DHCP server assigns permanent IP
address to requesting client.
Dynamic: DHCP server "leases" IP address to
requesting client. The IP address is only
valid for a limited period of time; after
which the client must request a renewal or
ask for a new IP address.
Network Management Processes
• Accounting management
- Facilitates usage-based billing. If
money is not exchanged, it identifies
consumption and possibly “abuse” of
network resources.
Network Management Processes
• Performance management
- Facilitates measurement of network
behavior and effectiveness.
-Examine network applications
- Protocol behavior
- End-to-end performance across an
internetwork
- Component performance of individual
links or devices.
Network Management Processes
Security Management allows the network
management to maintain and distribute passwords
and other authentication information. Security
management should also include generating,
distributing, and storing encryption keys.
– Audit logs should document logins and logouts
– Attempts by individuals to change their level of
authorization.
– Compressing data rather than storing less data
Network Management Architectures
Managed device: Routers, servers, switches,
bridges, hubs, end systems, or printers.
Agent: Network management software that
resides in a managed device.
Network management system (NMS): Is a
terminal with software that displays
management data, monitor and controls
managed devices, and communicates with
agents. Typically located in a network
operations center (NOC).
Network Management Architectures
• In-band monitoring is network management
data that travels across an internetwork using
the same paths as user traffic.
- Impacts ability to trouble shoot problems
• Out-of-band monitoring
- More complex and expensive
- Analog lines are used for backup
- Security risks with analog links need a
callback mechanisms
Network Management Architectures
Centralized monitoring architecture all
NMSs reside in one place of the network.
Distributed monitoring means the NMSs and
agents are spread out across the entire
internetwork. Distributed monitoring involves a
more complex network configuration and tends to
be harder to manage.
Manage-of-managers (MoM) is a distributed
arrangement with a central NMS. The central
NMS manages the distributed locations.
Network Management Tools and Protocols
A network management solution should include
tools to isolate, diagnose, and report problems and to
expedite recovery and quick repair.
– Interfaces can be CLI, GUI, and different browsers
– SMNPv3 should gradually replace versions 1 and 2
because it offers better security, authentication to
protect against modification of information, and
secure set operations for the remote configuration
of SNMP managed devices.
Network Management Tools and Protocols
• Management Information Bases (MIB) stores
information from local management agent on a
managed device.
- Each object in a MIB has a unique
identifier.
- Network management applications use the
identifier to retrieve a specific object.
- A MIB is a structured tree and
hierarchical structure.
Network Management Tools and Protocols
The MIB structure is logically represented
by a tree hierarchy. The root of the tree is
unnamed and splits into three main branches:
1. Consultative Committee for International
Telegraph and Telephone (CCITT),
2. International Organization for
Standardization (ISO),
3. Joint ISO/CCITT.
Network Management Tools and Protocols
These branches and those that fall below
each category have short text strings and integers
to identify them. Text strings describe object
names, while integers allow computer software to
create compact, encoded representations of the
names. For example, the Cisco MIB variable
authAddr is an object name and is denoted by
number 5, which is listed at the end of its object
identifier number 1.3.6.1.4.1.9.2.1.5.
Network Management Tools and Protocols
The object identifier in the Internet MIB
hierarchy is the sequence of numeric labels on the
nodes along a path from the root to the object. The
Internet standard MIB is represented by the object
identifier 1.3.6.1.2.1. It also can be expressed as
iso.org.dod.internet.mgmt.mib.
Internet MIB Hierarchy
Network Management Tools and Protocols
RMON Monitoring (RMON) developed to
close the gap in the standard MIBs which lacked
the capability to provide statistics on the data link
and physical layer parameters. The IETF
developed RMON MIB to provide Ethernet traffic
statistics and fault diagnosis.
- RMON collects CRC errors
- Packet-size distribution
- Number of packets in and out
Network Management Tools and Protocols
What does RMON support?
- Allows the network manager set
thresholds for network parameters
- Configures agents to automatically deliver
alerts to NMS.
- Capturing packets and sending the captured
packets to the MNS for protocol analysis.
- Provides information about the
health and performance of the network
segment.
Network Management Tools and Protocols
• Cisco Discovery Protocol (CDP)
- Specifies a method for Cisco routers and
switches to send configuration
information to each other on a regular basis.
- CDP runs on the data link layer
- Utilizes Sub Network Access Protocol (SNAP)
SNAP is the data-link address used in IS-IS protocol to
reach the neighbor on a broadcast media. This is
comparable to Ethernet links using the Mac Address of
the neighbor.
Network Management Tools and Protocols
By default, CDP announcements are sent every
60 seconds on interfaces that support Sub Network
Access Protocol (SNAP) headers,
including Ethernet, Frame Relay and Asynchronous
Transfer Mode (ATM). Each Cisco device that
supports CDP stores the information received from
other devices in a table that can be viewed using
the show CDP neighbors command. This table is also
accessible via SNMP. CDP frames are sent every 60
seconds. Switches and routers do not forward CDP
frames.
Network Management Tools and Protocols
View: Cisco CPD configuration video
http://www.youtube.com/watch?v=l9zfWyS0Bn8
Network Management Tools and Protocols
• Cisco NetFlow Accounting
– Collects and measures data as it enters router or
switch interfaces. The information enables a
network manager to characterize utilization of
network and application resources.
– Helps network manager visualize traffic patterns so
that proactive problems can be detection is
possible.
– NetFlow allows a network manager to gain a
detailed, time-based view of application usage.
Selecting Technologies and Devices
• We now know what the network will look like.
• We also know what capabilities the network
will need.
• We are now ready to start picking out
technologies and devices.
• Chapter 10 has guidelines for campus networks.
Campus Network Design Steps
• Develop a cabling plant
design
• Select the types of cabling
• Select the data-link-layer
technologies
• Select internetworking devices
• Meet with vendors
Cabling Plant Design Considerations
• Campus and building cabling topologies
• The types and lengths of cables between buildings
• Within buildings
– The location of telecommunications closets and crossconnect rooms
– The types and lengths of cables for vertical cabling
between floors
– The types and lengths of cables for horizontal cabling
within floors
– The types and lengths of cables for work-area cabling
going from telecommunications closets to workstations
Centralized Versus Distributed Cabling
Topologies
• A centralized cabling scheme terminates
most or all of the cable runs in one area of
the design environment. A star topology is an
example of a centralized system.
• A distributed cabling scheme terminates
cable runs throughout the design
environment. Ring, bus, and tree topologies
are examples of distributed systems.
Centralized Campus Cabling
Building B
Cable Bundle
Building A
Building C
Building D
Centralized Campus Cabling
Distributed Campus Cabling
Building B
Building A
Building C
Building D
Types of Media Used in Campus Networks
• Copper media
• Optical media
• Wireless media
Copper Media Advantages
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Conducts electric current well
Does not rust
Can be drawn into thin wires
Easy to shape
Hard to break
Copper Media
Coaxial
Shielded Twisted-Pair (STP)
Twisted-Pair
Unshielded Twisted-Pair (UTP)
Coaxial Cable
• Solid copper conductor, surrounded by:
– Flexible plastic insulation
– Braided copper shielding
– Outer jacket
• Can be run without as many boosts from
repeaters, for longer distances between
network nodes, than either STP or UTP
cable
– Nonetheless, it’s no longer widely used
Twisted-Pair Cabling
• A “twisted pair” consists of two copper
conductors twisted together
• Each conductor has plastic insulation
• Shielded Twisted Pair (STP)
– Has metal foil or braided-mesh covering that
encases each pair
• Unshielded Twisted Pair (UTP)
– No metal foil or braided-mesh covering around
pairs, so it’s less expensive
UTP Categories
• Category 1. Used for voice communication
• Category 2. Used for voice and data, up to 4 Mbps
• Category 3. Used for data, up to 10 Mbps
– Required to have at least 3 twists per foot
– Standard cable for most telephone systems
– Also used in 10-Mbps Ethernet (10Base-T Ethernet)
• Category 4. Used for data, up to 16 Mbps
– Must also have at least 3 twists per foot as well as other
features
• Category 5. Used for data, up to 100 Mbps
– Must have 3 twists per inch!
• Category 5e. Used in Gigabit Ethernet
• Category 6. Used in Gigabit Ethernet and future technologies
Types of Cables
• Mode is an allowable path for light to travel
down a fiber.
• Multimode fiber has multiple modes or paths
that light can follow. All paths are not equal.
some are longer, and the time it takes to travel
down each path more time consuming.
• Single mode contains a small core diameter, has
one path, supports higher bandwidth rate over
longer distances.
Optical Media
Multimode Fiber (MMF)
Single-mode Fiber (SMF)
Copper Vs Fiber-Optic Cabling
• Twisted-pair and coax cable transmit network signals
in the form of current
• Fiber-optic cable transmits network signals in the
form of light
• Fiber-optic cable is made of glass
– Not susceptible to electromagnetic force (EMF) or radio
frequency interference
– Not as susceptible to attenuation, which means longer
cables are possible
– Supports very high bandwidth (10 Gbps or greater)
– For long distances, fiber costs less than copper
Multimode
• Larger core diameter
•
• Beams of light bounce •
off cladding in multiple
ways
• Usually uses LED source •
• Shorter distances
•
• Less expensive
•
Single-mode
Smaller core diameter
Less bouncing around;
single, focused beam of
light
Usually uses LASER
source
More expensive
Very long distances
LED
Definition: A light-emitting diode (LED) is a twolead semiconductor light source. It resembles a
basic pn-junction diode, which emits light when
activated
Single/Multi-Mode Fiber
Multi-Mode Fiber
Ethernet
• STP is shielded twisted pair cabling.
• UTP is unshielded twisted pair cabling.
Typically found in buildings. Generally , least
expensive, lowest transmission capabilities
because it is subject to crosstalk, noise, and
EMI (Electromagnetic Interference).
• Coax cabling was popular in the 1980s and
1990s. Not used or installed as it was in the
recent past.
Electromagnetic Interference (EMI)
Internet Cables
Internet Cables
Just when you thought it was safe to run
internet cables in the water, it appears sharks have
developed the taste for data.
Video of shark biting under water cable
https://youtu.be/1ex7uTQf4bQ
Ethernet
• Ethernet is a physical and data link layer
standard for the transmission of frames on a
LAN.
- IEEE802.3 has evolved to support UTP and
fiber-optic cabling, and fast
transmission speeds.
- Gigabit Ethernet is targeted for the core
layer on enterprise systems.
Wireless Media
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IEEE 802.11a, b, g, n
Laser
Microwave
Cellular
Satellite
Cabling Guidelines
• At the access layer use
– Copper UTP rated for Category 5 or 5e, unless
there is a good reason not too
– To future proof the network
• Use 5e instead of 5
• Install UTP Category 6 rated cable and terminate the
cable with Cat 5 or 5e connectors
• Then only the connectors need to be changed to
move up in speed
– In special cases
• Use MMF (Multimode Fiber) for bandwidth
intensive applications
• Or install fiber along with the copper
Cabling Guidelines
• At the distribution layer use
– MMF (Multi mode fiber) if distance allows
– SMF (Single mode fiber) otherwise
– Unless unusual circumstances occur and cable
cannot be run, then use a wireless method
– To future proof the network
• Run both MMF and SMF
LAN Technologies
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Half-duplex Ethernet (becoming obsolete)
Full-duplex Ethernet
10-Mbps Ethernet (becoming obsolete)
100-Mbps Ethernet
1000-Mbps (1-Gbps or Gigabit) Ethernet
10-Gbps Ethernet
Metro Ethernet
Long Range Ethernet (LRE)
Cisco’s EtherChannel
IEEE 802.3 10-Mbps Ethernet
10 Mbps Ethernet
10Base5
10BaseT
10BaseF
2 pairs Category3 or better UTP
100 meters
Thick coax cable
500 meters
10Base2
Thin coax cable
185 meters
2 multimode
optical fibers
10Broad36
3 channels of a private
CATV system 3600
meters
IEEE 802.3 100-Mbps Ethernet
100BaseT
100BaseX
100BaseT4
4 pairs Category3 or better UTP
100 meters
100BaseTX
2 pairs Category-5 or
better UTP
100
meters
100BaseFX
2 multimode optical fibers
2000 meters (full duplex)
100BaseT2
2 pairs Category3 or better UTP
100 meters
IEEE 802.3 Gigabit Ethernet
1000BaseX
1000BaseSX
2 multimode optical fibers
using shortwave laser optics
550 meters
1000BaseLX
2 multimode or single-mode
optical fibers using longwave
laser optics
550 meters multimode, 5000
meters single-mode
1000BaseCX
2 pairs STP
meters
25
1000BaseT
4 pairs Category-5 UTP
100 meters
IEEE 802.3 10-Gbps Ethernet
10GBase with Fiber Cabling
10GBaseLX4
Multimode or single-mode
optical fibers
300 meters multimode,
10
km single-mode
10GBaseSR
Multimode optical
fibers
300
meters
10GBaseLR
10GBaseER
Single-mode
optical fibers
10 km
Single-mode
optical fibers 40
km
IEEE 802.3 10-Gbps Ethernet
10GBase with Copper Cabling
10GBaseCX4
XAUI 4-lane PCS
15 meters
SFP+ Direct
Attach
Twinax
10 meters
10GBaseT
UTP or STP
100 meters
Metro Ethernet (MAN)
• Service offered by providers and carriers that
traditionally had only classic WAN offerings.
• The customer can use a standard Ethernet
interface to reach a MAN or WAN.
• The customer can add bandwidth as needed
with a simple configuration change.
Long-Reach Ethernet
• Enables the use of Ethernet over existing,
unconditioned, voice-grade copper twisted-pair
cabling
• Used to connect buildings and rooms within
buildings
– Rural areas
– Old cities where upgrading cabling is impractical
– Multi-unit structures such as hotels, apartment
complexes, business complexes, and government
agencies
Cisco’s EtherChannel
Data Center Switch
800 Mbps EtherChannel
West Fiber Run
400 Mbps
East Fiber Run
400 Mbps
Wiring Closet Switch
Cisco’s EtherChannel
EtherChannel provides incremental trunk
speeds between Fast Ethernet, Gigabit Ethernet,
and 10 Gigabit Ethernet. EtherChannel combines
multiple Fast Ethernet up to 800Mbps, Gigabit
Ethernet up to 8Gbps , and 10 Gigabit Ethernet up
to 80Gbps.
Internetworking Devices for Campus
Networks
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Switches
Routers
Wireless access points
Wireless bridges
Selection Criteria for Internetworking Devices
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The number of ports
Processing speed
The amount of memory
Latency when device relays data
Throughput when device relays data
LAN and WAN technologies supported
Media supported
More Selection Criteria for Internetworking
Devices
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Cost
Ease of configuration and management
MTBF and MTTR
Support for hot-swappable components
Support for redundant power supplies
Quality of technical support, documentation,
and training
Summary
• Once the logical design is completed, the physical
design can start
• A major task during physical design is selecting
technologies and devices for campus networks
– Media
– Data-link layer technology
– Internetworking devices
• Also, at this point, the logical topology design can
be developed further by specifying cabling
topologies
Review Questions
• What are three fundamental media types used in
campus networks?
• What selection criteria can you use to select an
Ethernet variety for your design customer?
• What selection criteria can you use when
purchasing internetworking devices for your design
customer?
• Some people think Metro Ethernet will replace
traditional WANs. Do you agree or disagree and
why?
This Week’s Outcomes
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Network Management Processes
Syslog
Security
Campus Cabling
CDP
• Technologies
• Selection Criteria for Internetworking Devices
Due this week
• 10-1 – Concept questions 7
Next week
• Read Chapter 11 in Top-Down Network Design
• 11-1 – Concept questions 8
Q&A
• Questions, comments, concerns?