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Wednesday, September 25, 2019

Network Design Part 1

cisco design!!

1 plan:
- design
- assessment
- strategy & analysis for solution


2 build
- validation
- deployment
- migration 


minimumly distruptive as possible!


** achieve bisnis goals. -> minimize operational downtime of network infrastructure.


3 manage
- product support
- solution support
- optimization
- operations management



==========================

di plan phase bakal banyak


HLD / HIGH LEVEL DESIGN
LLD / LOW LEVEL DESIGN
BOM / BILL OF MATERIAL


=========================

- Network life cycle model

PPDIOO


prepare
plan
design

^ 3 ini masuk kategori plan


implement

^ build



operate
optimize

^ 2 ini masuk kategori manage






dari atas ke bawah, trus ke atas lagi.








====================

PPPDIO part2


1 prepare phase. ( high level )

proposing solution.
financial justification.
identify particular technology that suit organization.



2 plan

make more details!
characterizing existing network. putting particular goal in baseline.



3 Design

before implemen.
make sure business and technical goal fit in.
creating design

each solution scalable.
perform at spec
high available?

^ 3 metric ini paling penting



4 Implement
least distruptive existing infra.


5 Operate



6 Optimize
day to day check and optimize!


====================


characterize existing nework

- network maps
- network addressing and naming
- wiring and media
- architecture / environtment constraint
- network health  :

prepare checklist to make sure the network is healthy!




cisco provide us with nice starting point for analyze health of our existing network as we plan to redesign.


- ethernet segment should not feature a sustained utilization 40% or higher.


- all ethernet segments should be switched -- no shared segments ( hub-based )

- no WAN link should feature a sustained utilization 70% or higher

- response time should be generally less than 100ms

- LAN response time should generally be 2ms

- no segments have more than 1 CRC error per million bytes of data

- no segments should have more than 20% multicast / broadcast traffic


- for ethernet segments, there should be less than .1 percent collisions over 5 min intervals.


- CPU utilization should not exceed 75%

- number of output queue drop should not exceed 100 in an hour

- number of input queue drop should not exceed 50 in an hour

- number of buffer miss should not exceed 25 in an hour




========================== 


identify
network audit
analyze



=========================


existing documentationn
existing management software
additional auditing tools


=======================

bisa lewat cli. show command.

atau pake tools kyk cisco prime infrastructure. / solarwind

polling graphic/resource via SNMP.

======================


MIB = database of variables. diakses oleh NMS buat analisis data.

SNMP 1
SNMP 2c
SNMP 3    -> ++ authentication, integrity, encryption



=====================


CDP  -> cisco prop
LLDP -> vendor neutral ( link layer discovery protocol )
Netflow ->  built in within cisco router



====================

komponen netflow:

- monitor / traffic monitoring
- exporter / gathering information and sending to device
- collector


exporter:


# flow exporter NF_1    !! give name
# destination 12.12.12.100    !! ip dari collector
# transport udp 9996    !! choosing port number
# source serial0/0   !!select interface klo ada banyak interface
# exit


monitor

# flow monitor NF_MON1
# exporter NF_EXPORTER1
# record netflow-original




!! assign monitor

# int serial 0/0
# ip flow monitor NF_MON1 input   !! direction
# end


!! test

# show flow monitor name NF_MON1 cache 



===================

IP SLA.

testing the network delay using UDP packet based jitter!

^ penting buat VOIP


R1------------R2



!! create responder

R2# ip sla responder udp-echo ipaddress 12.12.12.2 port 5000

 

!! generate traffic

R1# ip sla 1
# udp-jitter 12.12.12.2 16384 codec g711alaw 
# frequency 30          // change default 60s to 30s



!! schedule ip sla test

R1# ip sla schedule 1 start-time now life forever



!!  check on r2
R2# show ip sla responder

R1# show ip sla statistics 1


==================


!! design network.

OSI model -->  design from top or bottom??


APP first?

cabling first?




design from bottom up cons:
- fast
- based on prev experience
- org reg
- failure problem   -> high probability

^ need VOIP?  buy cabling first, router, Gigabit ethernet, xyz






design top down :
- big picture
- time consuming

^ requirement of technology / application
^ need validation design.

2 method:
prototyping -> construct in lab environtment
pilot  -> use small portion of production. 
    use small data. actual user, actual action.
  connected to production network





=================


!! building modular network


core
distribution
access





modular --> troubleshooting quick


MTTR = mean time to repair.



break network into smaller convergence domain!
ospf area 0  -> dipecah jadi banyak area






1 convergence domain
2 scalability
3 resiliency  -- network can take more overal fault.
=================


campus network:
- campus infrastructure
- datacenter



edge network:
- e-commerce
- internet connectivity
- remote access
- WAN connectivity


ISP:
-ISP1
-ISP2
-WAN

remote network:
- teleworker
- enterprise branch
- enterprise datacenter


====================== 


!! applying modularity


think hierarchical


- hub and spoke


- core, dist, access


core layer: speed,speed,speed  // biasanya antar core layer di aggregate / etherchannel.



dist layer: aggregate, summarize, security policy   ( biasanya multilayer switch, high speed port  )
access layer: wired, wireless. ( mac based, not routing )




- collapsed core ( 2 tier topology )
^ core and distribution combined become 1 device  ( saving cost )
^ access layer tetep ada.
^ tapi ga cocok buat large campus, yg punya banyak building.




- multilayer

===================


!! virtualization

physical vs logical  : VLAN


segregation :  VSAN
desegregation : connecting 2 dataenter long distance virtualization ->  OTV / OVERLAY TRANSPORT VIRTUALIZATION.

^ JADI SEOLAH2 CONNECT SECARA L2 walaupun beda lokasi.



density / resource workload = how much ram / cpu per server. ( utilization )


High availability




==========================


VSS = virtual switching system.

^ multiple virtual switch connected!



=======================

!! consequence

1 fate sharing
^ kerusakan di 1 physical bakal ngefek ke beberapa virtual

2 suboptimal pathing
^ assymetric routing

3 overuse virtualization


=====================


nexus -> creating VDC / virtual device context



========================

!! campus design


end to end vs localized vlan approach 
* best = localized  ( simple, scalable )



end to end = differentiate sales vlan, hr vlan.



!! geographical
1st floor = vlan_1
2nd floor = vlan_2




====================

HSRP = CISCO PROP
VRRP = IETF
GLBP = GATEWAY LOAD BALANCING  // using virtual mac.



!! best practice vlan
vlan default 1 => change.
^ ketika ada switch baru ga make default vlan. improved security
================

802.1D = legacy stp
802.1W = RAPID SPANNING TREE PROTOCOL
802.1S = MSTP

================

!!stp protocol
BPDU GUARD = put on access port on server / workstation.
ROOT GUARD = protecting new switch become the root bridge
LOOP GUARD


================


vss = virtual switching system. tied multiple switch become 1 ( logical )


cisco stackwise =  using stacking cable

==================




!! designing enterprise security


defense in depth concept.  ->  layer of security.

attacker -> 1 layer then next layer  -> tighten !



!! physical 
^ use password security on console port device.


!! os security
^ device hardening

ex: auto secure di cisco


# auto secure
^ function :    disabled unused service on interface ( scripting )
setting enable secret password
edit login banner
configuration local user database
setting blocking period ( how many second time after login failure )
setting maximum login failure attempt
configure ssh
configure CBAC firewall







===================

firewall security

packet -> ACL
stateful firewall -
Application layer gateway -> proxy
Next Generation  -> look deep inside application traffic, apply IPS, Malware guard.







===================

cisco ASA ( adaptive security appliance ) -> NG Firewall


!! define inside network
!! define outside network

!! allow all inside, allow only appropriate several response from outside network.



# show nameif    !! check interface name in ASA, security level
^ 0 = untrusted, 100 = completely trusted


# show run int gi0/1 !! check config interface



==================
Security firewall


!! Intrusion detection system
IDS -> have database of signature attack , recognize most form of attack   ( inform the user there is an attackk!!! )



!! Instrusion prevention system
IPS -> drop known attack


cisco asa bisa dimasukin FirePower module
^ buat upgrade jadi fitur IPS
^ ++ URL Filtering, Application inspection, anti malware.



FW ++ IPS ++ NAC + AAA

NAC = meet defined posturing ! , correct patches, OS before entering network




multi factor authentication!
=================

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